I don't know if this would work on the benchtop, but...
About 9 years ago, I was teaching an EM tech how to do special stains.  We left some Grocott stained slides in Fisher Hemo-De (citrus based xylene substitute) a couple of days before she got around to coverslipping them. =20
The silver was gone.  I've never tried to repeat this and don't use  Hemo-De anymore (no one could stand the smell of the stuff); so, I don't know if it was just a fluke or if Hemo-De removes silver.
Do any of the brilliant chemist types out there know why Hemo-De would have removed the silver?

Julie Collins
Dir, Immunohistochemistry
Univ. of Kansas Med. Center
Kansas City, KS