I have a toolbox with a bunch of tools in it. In addition, I have a large plastic box where I keep all my bolts and nails in a disarray.

Some of the bolts are a little rusty, and some of my tools (e.g. screwing bits) are rusty, and now I am concerned as to wether storing them all together (some of them touching each other), might induce the unrusted tools to rust as well.

Of course a thorough (i.e. scientific) explanation would be even more appreciated.


2 Answers 2


Rust is not mould, rust is oxidization of the metal and cause by the oxygen in the air.

Most tools, nuts and bolts have a rust proofing in the form of a light coating of oxidization (often of a metal that's not iron) that will isolate the material underneath from further rust. A scratch in that coating will then let the rust spread again.

For long term storage you can oil the tools.

  • Iron oxide is slightly soluble. As a consequence, rust will migrate in the presence of water and will not remain as an effective protective coating. Many tools, nuts, bolts, etc. are coated with zinc. If zinc and iron are in contact with each other and with water, galvanic action will cause the zinc and iron to be electrically charged relative to the water, thus hastening corrosion of the zinc, but essentially blocking corrosion of the iron. Many naval vessels have bare steel in contact with seawater, but do not rust because they have have zinc plates to protect them.
    – supercat
    Oct 12, 2015 at 7:25
  • What kind of oil? And do you leave the oil on?
    – einpoklum
    Jan 11, 2019 at 0:24

Rust doesn't spread from one tool to the other.

The theory that I go by with my tools is that dirt and sawdust draws moisture, which leads to rust. Clean, well-maintained tools with a wipe down with oil will last quite a long time.

Throw a piece of chalk in your toolbox, after cleaning everything out.

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