I have ancient roman coins from AD and BC. I need to know the proper way to clean them with out ruining them?? O yea and they are bronze but, they have a lot of build up on them.

I found this site a couple weeks ago when I discovered a roman coin in my attic. Hope it helps.

Ancient Coin Cleaning And Restoration: Cleaning Ancient Coins Using Various Methods (http://ancientpeddler.blogspot.com/2007/02/cleaning-ancient-coins-using-various.html)

I thought you don't clean them...

Ultra sonic cleaners work fairly well.

I thought you don't clean them...

Sometimes you don't clean them, but when the dirt and rust is so much that you can't see the details of the coin you need to clean it.