Nitric Acid Is The Hot New Way To Pick Locks

Lockpicking is a grand skill to have, and one that’s often presumed to be one of the dark arts of the burglar. However, a new technique has come to the fore in some European contexts. It appears nitric acid is being used to damage locks to allow criminals to gain entry into residential premises.

Germany’s Bild has covered this matter, as has Feuerwehr Magazine. The technique has apparently come to prominence in the last couple of years. Attackers pour the corrosive liquid into the keyway of a typical door lock. This damages the cylinder, and perhaps the pins inside as well. Once the metal has been eaten away and the structure of the lock is sufficiently degraded, it can presumably be forced open quite easily with hand tools. The technique is apparently especially effective in Germany, where locks are typically installed with the pins facing down. This makes it easy for any liquid trickled into the lock to eat away at the pins in the bottom.

German authorities advised people to be on the look out for discoloration around door locks. If seen, it’s important to avoid contact with any corrosive liquid that may have been used on the lock.

It’s a nasty technique that doesn’t just damage locks, but doors as well! Meanwhile, if you’re learning the art of lockpicking, just remember not to practice on any important locks you might actually need. More pictures after the break.

60 thoughts on “Nitric Acid Is The Hot New Way To Pick Locks

    1. Picking is a method used when not leaving traces is a requirement, ie to avoid detection longer or attempt claims that no break-in occurred.

      Brute force is when that isn’t a requirement. As this method wouldn’t be silent either, there is no advantage over kicking the door frame in or breaking a window, both of which are quicker, easier, and faster.
      This method just adds disadvantages for no reason at all.

      1. Picking does leave traces if the usual “fast” methods are used, in the form of tell-tale scratches. Pros can do it carefully enough to avoid the marks, but it takes a bit longer.

        I think this acid attack is for people who can’t be bothered to learn basic lock picking. And perhaps that’s why they are burglars to begin with… low IQ.

        1. Why use a key when you can use a rock?

          No one learns lockpicking to burgal. Its way to slow. Shake the door and move on. If there’s a window, break it. If you’re so inclined use a halligan and and an axe.

      2. > As this method wouldn’t be silent either, there is no advantage over kicking the door frame in or breaking a window, both of which are quicker, easier, and faster. <

        In Germany at least the first option – kicking the door(frame) in – often is not reasonably possible because both door and frame of the outward facing doors are very sturdy (specifically strengthened – maybe more so in big cities than in rural areas).
        Melting the lock with acid would be faster, easier & less noisy (no, not quicker too because it's already faster…).

        And breaking in through a window may not be as easy as you think either (not on ground floor, better or reinforced windows). I'm pretty sure most normal/common/typical windows in Germany are a lot stronger than the common ones in USA.
        You can't just shove in a crowbar and pry a window upward(!) in Germany (same in most of Europe I think) – if closed they're locket in place in 4-8 points all around the frame (AFAIK).

        1. The euro-style multipoint locking door is something Americans really underappreciate.

          But when you think about it – relying on a single point of failure to lock an exterior door is kinda crazy. The more places the door attaches to the frame, the stiffer it is.

  1. Had a nitric acid leak on the bottom shelf of a wooden chemical cabinet. Ate a huge hole and began eating the concrete below before it was discovered. Keep plastic trays under the bottles now just in case.

  2. Reminds me of a Sherlock Holmes cartoon I saw as a kid.
    Most locks I’d just pick it or use a bump key, as the people I’ve helped didn’t want to buy new locks, but I guess if your skill is too low (as in this case) or it’s a really complicated lock, then it’s time for overkill.

    1. May not be a skill issue at all, just a matter of convenience and stealth – I could see carrying a small bottle of ‘oil’ and lubricating the lock/hinge of a great many doors without attracting any attention at all and no matter how complex the lock the acid likely worked wonders rather quickly. Probably not as fast as a talented lockpicker, but not needing to be a really talented lock picker or do the recon to have the exact right style of bump key for the lock model prepared …

  3. I’m pretty sure our old VW beetle also has the ignition key installed with the pins on the bottom. I always wondered about that – would not have guessed it was a German thing.

    1. Can confirm. German locks are installed “upside-down”.

      I always wondered if there’s extra risk of getting crud caught in the mechanism, but I figured most of it probably gets pushed through. But rain? Or, apparently, nitric acid.

      1. Germans probably remember to lubricate their locks from time to time, so having it be easy to get the lubrication into the important parts… I have no idea if that is the thinking, but it does actually make sense.

  4. And the method is no longer limited to Germany, it’s spreading in other European countries as well.
    I hope some method to mitigate or prevent emerges relatively soon.

    1. Stainless steel or plastic lock cores is probably the mitigation. A lot of locks are largely zinc. Easy to corrode, and barely enough strength before it gets eaten away.

        1. Acid based drain cleaner is diluted to 30-50% sulphuric acid and with any nitrate salt it will create nitric ions cutting through any copper-based alloy – most pins are made from brass.

    1. It’s not very hard to make. There are hundreds of diy setups on youtube that use nothing more than a couple of bottles and tubes and a high voltage supply. It can also be made by reacting other commonly available chemicals.

  5. Hmm, now that is a tough one, because I rather not go to Ukraine or Belarus or in fact Estonia and Poland at this time thank you very much.

    Also: Is that ‘capital’ status shared with France and Belgium and theNetherlands and the UK and ireland? Oh and uhm Spain and what have you, Sweden? Etcetera etcetera.

    1. Kiev is a very safe city to live, I know because that’s where I studied informatics and met my gf (now wife) and lived with her for 5 years until Feb. 2024 when we moved to Lublin. If living in Kiev the war is only in the east regions and it’s literaly like distance from Berlin to Warsaw (over 500 km).

      Belarus is wonderful country too with good culture, very clean, very safe and they have kvass~! Best drink to hot summer days. Too bad Luka is doing stupid things but he’ll lose next elections so it might be better. Also, very cheap petrol in Belarus. And they make nice motorcycles (I’m lusting for M1NSK TRX).

      Poland is a good country too but unfortunately it’s in EU so it’s not as safe as UA or BY. People are sometimes very offensive.

      1. I have too many opinions to be safe in Ukraine I think.
        Same for Belarus, where incidentallt I don’t think you’ll see any fair or even half-way fair election the coming decades.
        As for Poland, I don’t like some of the things going on there politically, and I don’t like their embrace of the US and anything the US thinks up to be assholes.

        Oh and on the list of things I do not like religion is near the top, and there is a bit too much of it in the east these days, including in Russia and Poland and most other eastern european countries.

        But I do like your positive attitude though, so don’t let my peculiarities get into the way of that :)
        And I think you might get that bike, it’s not the most expensive one after all, so it must be doable.

  6. Amateurs. We had a spate of bike thefts on campus where the locks would be found in broken pieces near where the bike had been locked. Taking a good deal of time to put 2+2 together, the campus police finally insisted on a padlock for the liquid nitrogen tank in the physics building loading dock area and the problem went away.

    1. Yup liquid nitrogen was a thing when I worked at the university in the late ’80s.
      I think we only got about 3 years between unbreakable U locks becoming widespread, and liquid nitrogen breaking them.
      Now there are battery angle grinders, and it is very hard to make anything that they can’t get into.

      Some of the posters above finger immigrants, but I have to say that universities and youth hostels were the worst nests of thieves I ever came across. Privileged youth meets limited budget for the first time.

  7. Just for additional context: BILD is a populist tabloid, fostering fears about increasing crime and worse stuff. So this is right up their alley. Please take this into account before putting too much weight on their reporting.

    1. This, exactly.

      Bild is better than the National Enquirer, but not by much.

      ——

      As an American in Germany, Bild helped me learn the language – it uses simple sentences with simple words to reach the masses.

      Outside of that, the Bild concentrates on spreading fear, stirring the fires, and kicking up shitstorms. It’ll often have rabid, conflicting articles on the same page for maximum flame.

  8. I wonder what could be done to prevent this. Making everything out of stainless steel would help, instead of mild steel and brass pins. Maybe add a kind of relocker pin, like they do in safes, where the lock is permanently locked if acid is used?

    1. Ah yes, as I remember it the lyrics went…
      “Some die of drinking water, and some of drinking beer;some die of constipation and some of diarrhea; But of all the world’s diseases, there’s none that can compare; with the drip drip drip, of a syphilitic prick, of the British Gonorrhea”

  9. Nitric acid is not the “hot new way” of picking a lock. It is just an acid. And I think it would also be effective if the pins are on the upside of the lock.
    However, this is a method only a few criminals would chose. Like the ones who use explosive gases to open up ATM machines. But for usual burglary, it is way too much. Most people do not even lock their door, especially when they are just half an hour away for shopping or something. Most people still buy cheap cylinders and many doors can just be kicked, although not the ones in newer buildings in big cities. But of course that makes noise, which alarms the neighbours.
    There are so many methods to unlock a door … and windows, of course. If nothing works, you can still just ring the bell.

    1. If the pins are in the bottom gravity is working with you to get and keep the acid at the actually important bits of the lock mechanically, and you can squirt it into the keyhole and actually get right to the good stuff – so sure eventually if all the important bits are at the top and you feed in enough acid in the right place you’d get enough of it at the working bits to bust the lock… But a few small thin pins with the acid actively pouring through them when you put it into the nice large keyhole will undoubtedly cease to function first.

      Also ‘most people do not even lock their door’ type comments might be true where live but really won’t be true everywhere. Being Germany I’d not be shocked to find the minimum quality of lock you can actually buy isn’t better than the ‘premium high security’ lock fitted most anywhere else in the world, and that it is always locked as you leave the house – they are one of if not the nation famed for over engineering and following rules.

    2. Doors in Germany lock automatically when you close them. They have only a keyhole from the outside. If you leave your house or apartment without the key, you are going to have a hard time getting back in.

      1. Do they double lock though?

        One locked myself out of a villa in Spain, locksmith cost a pretty penny for 5 mins of work, he has a special strong but thin sheet of plastic, barely bigger than playing card: push it in the door where the lock is, and keep the pressure on, and boot the base of the door a couple of times. Door opens.

  10. Yeah, that’s not lock picking, that’s brute force entry.

    Lock picking is usually non destructive and you usually can’t tell that it’s been picked without looking at the inside of the lock.

  11. What if the lock had a proximity sensor, and blew out compressed air?

    No effect on someone inserting a key (or a lock pick). But anyone playing with nitric acid, could suddenly have a Really Bad Day.

  12. This feels like a bit of sensationalist journalism (esp. if the comments about Bild are to be believed) about something that seems to be a pretty slow & inefficient way to gain entry – pour a restricted and nasty chemical into the lock, create obvious and easily spotted damage, have to wait for the chemical to act & come back later to attempt entry?

    As another commenter said – professional burglars will do any number of things to gain entry and lock picking is rarely one of them.

    1. In the context of home automation, I often see negative comments towards smart door locks, usually mentioning how a burglar could hack in your WiFi and deactivate the lock. The answers is always a resounding NO! a burglar doesn’t have the time or brain power to do that. He will just pick a brick or a stone that you put as decoration in your garden and put it through a window.
      The security of a building is only as good as its weakest point.
      Locks are there just to keep honest people honest.

  13. The bible being flipped in European locks is key to this attack. That allows the acid to pool around the pins. It isn’t a bad idea in certain circumstances for criminals though. Stop by a door and inject the acid. Walk away come back 5 minutes later with a screwdriver the lock just turns like you have the key. It is a very low exposure technique with minimal time spent at the locked obstacle. It is very quiet and looks less suspicious that even picking if you leave the area while its cooking.

  14. When it rains with blowing wind and then the temperature freezes the pins should always be up, gritty dust from pockets falls out not accumulates and jams. This is for everyone even in the dessert. Teeth up for a reminder when handling keys in the dark.

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