The story comes from "Long After Midnight", as far as I can remember, and I haven't read it in English, but it's the English name of it that I am looking for. It is about a guy who invents a rust machine which is going to destroy all weapons on Earth.

* Story, not "Stroy", naturally. Sorry about that.

I believe this is "A Piece of Wood", found in LONG AFTER MIDNIGHT and also in THE STORIES OF RAY BRADBURY.

- Phil

Thanx, that's what I was looking for!