Jochen writes: Another tip from the school of hard knocks: never sniff glacial acetic acid to see what it smells like :-). Rather pure acetic acid of varying concentrations is sold in photography supply stores as stop bath or a hardener add-in for fixer. Certainly pure enough for PC cleanup followed by a wash. You want a concentration way way less than "glacial" (99.5% acetic acid) but much more concentrated than the typical percent or two used in stop bath working solutions. Get it with the indicator in it (most common form for photography) and you'll know that you're done washing/rinsing when it stops turning purple. Tim.