I'm not sure if the question is on-topic here, since it's about tools and not exactly mechanics, but if it's not I can move it to the appropriate SE!
I have a power drill and used it once at work to fix a problem we had there. It was used close to an oxidizing chemical and I believe because of that the folder head started rusting a little bit. Before it got too serious I used sandpaper and removed the superficial rust, then applied rust converter (it doesn't look much pretty now since the rust converter creates a black layer, but I'm more concerned about protecting it).
There are some types of oil that are also used to prevent corrosion and I have some old engine oil here. I was wondering if I applied just a little bit of it, if it would also help prevent rust from coming back.