This method will work for light rust stains, such as if you set something rusty on a wooden surface for a short period of time and it left some residue behind. It won’t work for deeper rust stains, such as from a rusty nail that had been embedded in the wood for a long time or an old tool that was sitting on the wood for a long period of time.
Keep the bottle with the solution handy so you can moisten the stain again as you clean it.
You can use another kind of soft-bristled brush if you don’t have an old toothbrush around. Just make sure you don’t use anything that will damage the wood, such as a hard-bristled wire brush.
If the stain did not come off using this method, you will need to try bleaching the stain with oxalic acid.
This method is recommended for tough rust stains, such as when a metal object has been left in or on the wood for extended periods of time (like a nail or an old tool). It also may alter the finish of wooden objects that are painted or have a lacquer on them, so it’s important to test the cleaner first.
Oxalic acid is toxic and can cause extreme irritation and even burns if you get it on your skin or in your eyes. If this happens, rinse the affected area off immediately under cool running water for at least 15 minutes. If a burning sensation continues, then call 911 for assistance.
Oxalic acid is a common powdered household chemical that you can buy at a home improvement center or anywhere else that sells household chemicals. It is sometimes sold under a unique brand name and marketed as a rust cleaner.
If the wood is small enough to do so, it’s a good idea to put it on top of a workbench or another surface that you aren’t worried about damaging.
Don’t use a metal bowl because the oxalic acid might damage it. A glass or ceramic bowl are the safest options to use.
Dip the toothbrush into the bowl of water as you go if you need more water to turn the powder into a paste.
Don’t worry if you can’t tell whether the stain is gone through the crust, you will be able to check after you wipe it off and repeat the process if necessary.
This will allow you to wipe the cleaner off of the surface and see the results underneath it.
If the stain is still there after you completely wipe off the oxalic acid, then repeat the process from the beginning to remove it. If the stain is not gone after 2 applications, then you might need to sand and refinish the wood to remove it.
