So it sounds like they were exposed to salt water for those ten years? What do they look like? It would be useful to see a picture or two (you can upload pics using the "Upload Files" button when replying).

Coins should never be cleaned. Read this article for more information on why: Why you shouldn't clean your coins.

We would suggest starting with gently rubbing them with water using either your fingers or a microfiber cloth. That's pretty much all you would ever want to use on coins to avoid damaging them. Please do post some pics if you can.