I’ve discussed rust removal before, but some people swear by removing rust with vinegar. I never had much luck with it, but I’ve learned the secret.
The secret to rust removal with vinegar is to rinse the part thoroughly with hot water, immediately. If you don’t rinse it fast enough, or with hot enough water, the part will flash rust. But if you rinse correctly, vinegar is a cheap and effective way to remove rust from toys, old tools, and anything else made of iron or steel. I mostly use it on toy train parts but anyone who deals with anything old needs this trick.
Pros and cons of using vinegar
There are two major problems with using vinegar, in my experience. Maybe three. One you can do something about, and the others you have to live with.
The first problem is that removing rust with vinegar will also remove any plating that remains on the metal. If the part is thoroughly rusted, there’s no plating left, but in the case of electric train track, the plating inside the track could be just fine even if the outer surface is rusty.
That’s why I don’t recommend vinegar on track. I recommend aluminum foil. It’s more work, but it’s cheaper, probably faster, doesn’t harm the plating inside the track, and if any plating happens to remain on the outside, it doesn’t hurt that either.
The second problem with vinegar is it doesn’t leave any protective coating behind, unlike some commercial rust removal products. If you keep the de-rusted item in a climate controlled environment there’s little chance of re-rusting, but if you ever store it in a garage or a damp basement, don’t be surprised if it rusts again.
The third problem is flash rusting. If you don’t get the part rinsed properly, the part will re-rust in seconds.
Removing rust with vinegar
Caveats aside, removing rust with vinegar is easy. Place your part(s) in a plastic tub, pour in enough vinegar to cover it, and let it soak. Sometimes a few hours is enough. Sometimes it takes days. It’s a convenient way to deal with rusty Erector set screws, for example.
Once it’s been soaking a while, you can speed it up with a wire brush. Just brush off what you can with the brush, and return it to the vinegar bath if it’s not quite done.
When you’re satisfied with how clean the part is, it’s time to remove it and rinse. How you rinse it is important.
Preventing flash rusting with vinegar
Whoever named it flash rusting wasn’t exaggerating. In a matter of a few seconds, you can see rust reforming on the part. It will usually be lighter than what you cleaned off, but it’s disconcerting to watch your newly cleaned part re-rust that quickly.
The trick is to rinse it immediately with very hot water. Hot tap water isn’t hot enough. It doesn’t have to be boiling, but consider hot enough for hot coffee the minimum. I recommend you heat up some water in a large pot, as if you were making spaghetti. It doesn’t have to reach boiling, but it needs to be close.
Take the tub to your kitchen sink, remove the part and put it in the sink, and then quickly but not hastily (don’t burn yourself) bring your pot over to the sink and pour the scalding water over the part. The hot water will rinse away the vinegar, then evaporate quickly enough that your part won’t rust.
If you do get a small amount of flash rusting, rub the flash rust with a bit of aluminum foil to remove it.
Once the part dries, paint or coat it with some oil to prevent re-rusting, as long as you don’t need the part to conduct electricity.
Other uses for vinegar
Vinegar is a good cleaner because of its mild acidic properties. It does a nice job of removing mineral deposits in toilets and even battery acid and other yuck that turns up on circuit boards. I use it for enough different things that I find it useful to keep a gallon of cheap white vinegar on hand regularly.