Coins are one thing and you have to know what you have before you attempt any cleaning that may harm it. Soaking in olive oil is pretty safe. NEVER rub a coin when cleaning. Always pat dry. If you think the coin is valuable, check with the grading services for their advice on cleaning. If it is really valuable and you have it slabbed and it comes back "cleaned," all the value just went out the window.
As far as other stuff, I have found a few things that work pretty well. Soaking rusted material in WD-40 loosens up most of the rust. CrudKutter (sp?) makes a product that will remove rust from most items. It is non-toxic and works better than you would think. I also use a bluing and rust remover from a gun shop. Works good on rust.
I also have a series of brushes that get progressively harsher - plastic bristles, brass bristles, Stainless Steel bristles, steel bristles.
For small silver things, put it on some aluminum foil, add a little salt, drop of lemon juice (or spit works too) fold tightly together. It will heat up pretty good and even smoke sometimes. Works best for small flat things.
Electrolysis is good too but can eat your stuff is you leave it too long (personal experience). For some reason, I have found Balsamic vinegar works better than lemon juice.
Just some thoughts.
Daryl
