Quote Originally Posted by resummerfield
I would suggest "PEC-12 Archival Photographic Emulsion Cleaner". It comes in a 4 oz pump-spray bottle, and is sold by most phtot stores, like B&H, etc. I've used it on silver-gelatin with no problems.
I use PEC-12 often but I would caution that, while it is good for removing grease and fingerprints from film and prints, it does not really help with stains or any type of non-greasy grunge that may have built up. If the images are easily removed from their mounting, I would start by washing them. They can easily be soaked in water, they were washed for a long time once before, right?

You may find this site useful.