Removing Deep Gun Rust (and Bluing) at Home with Vinegar

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As a trained gunsmith, I find restoration and refinishing to be very rewarding work. I love the feeling of taking something worn or neglected, hand refinishing, and restoring it to some of its natural glory. Naturally, I spend some of my free time browsing pawn shops and used gun stores for neglected treasures. Recently, I found one; a Used Mauser HSc pistol in 7,65mm Browning for $145.

The big problem with the handgun is that it was sorely neglected. It was rusted to the point that serial numbers and other markings were almost impossible to identify and it was evident that the rust had begun to take deeper hold, pitting the metal. It wasn’t even immediately clear whether it would be possible to restore it or even safe to fire it, but for the price and the uniqueness I decided to take a chance.

Although I do gunsmithing daily, I work for a big company under manufacturing so I must do all my gunsmithing at home in my one-bedroom apartment. All of the equipment I want to use must fit (cleanly and safely) in this environment, so I am always looking for simple methods to improve the efficiency of my work.

While browsing the internet one day, I found a trick that seemed so convenient I had to try it myself. It goes like this: vinegar, being a mild acid, has naturally de-oxidizing properties that will break down rust and make it easier to remove from the surface of metal. Unlike sandpaper or abrasive blasting, this method does not rough up the metal, remove markings, or remove material when done properly. Other chemical strippers such as muriatic acid are much more efficient, but vinegar is cheap, easily available, and very safe to work around. It’s important to note that since bluing is an oxide, vinegar will also remove the bluing. This was actually not a negative for me as I plan to re-do it in a rust blue finish.

I went to Wal-Mart and bought a large tupperware container and a gallon of distilled white vinegar, totaling about $5. The only other tool I used was a stainless steel carding brush I bought from Brownell’s for rust bluing.

First, I detail stripped the gun and bagged the small parts together with other parts of their operating group.

I put the parts in the tupperware container and filled it with the vinegar. Almost immediately, bubbles started forming. I let it sit for 15 minutes at a time and then carded it briskly with the brush.

Soaking in vinegar

It took a little over an hour of this soaking and brushing cycle to remove a large portion of the rust. The vinegar slowly went from clear to deep orange as the rust seeped out from the pores of the metal. After I was satisfied that I had achieved all I could, I poured out the vinegar and quickly filled the container with dish soap and boiling water to flush out and neutralize the vinegar (it will, over a long period of time, etch metal if not neutralized). Then I removed the parts, dried them, and added a light coat of oil.

Parts flushed with water after vinegar, now (mostly) rust-free!

I was very impressed with the results. Almost all of the rust was removed, and it was hard to believe I was looking at the same pistol after only an hour of intermittent scrubbing. The metal actually looked reversed to its in the white state, showing even original machining and grinding marks.

The once heavily rusted barrel

After rust removal, I was even able to see more of the manufacturing marks. The serial number was clear and easy to read, but more exciting were the acceptance stamps located on the gun. The Waffenampt acceptance stance of an eagle with letter “L” indicates it was produced in Nazi-controlled Germany during WWII. Being a smaller caliber handgun, my reading indicates it was likely to be issued to an Officer who would have had it more as a symbol of status than a likely need to use it as a combat arm. It would have been issued with a black leather holster and two magazines serialized to the gun, neither of which were included with the sale. Regardless, it is a very cool piece of history to wonder about and I look forward to restoring it to high-quality bluing. There will still be some minor rust and pitting to remove, but it is already looking much better with this easy trick!

Acceptance stamp
Mauser-Werke slide
Magazine

I also have a Youtube channel (https://www.youtube.com/user/MrDakotapotts) where I document gunsmithing and, more recently, my journey to start competitive shooting. If you enjoyed this content, check out the video at the top of the article and consider subscribing to see more!

4 COMMENTS

  1. Thanks for providing such great useful resource on gun cleaning at home using vinegar.

    Just wondering about whether we can also use ammonia in its place as few users claim to see good results using ammonia also!

  2. Although I haven’t needed to use it on a firearm, I use citric acid to clean old hand tools that I restore. For best results, de-grease the item(s) to be cleaned before immersing them in the acid.

    Citric acid powder is available inexpensively at brewing supply stores (and other sources). Like vinegar, it’s safe to work with (it’s in all citrus fruits).

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