Sometimes I used Kodak Rapid Fix with Hardener for paper (don't ask me why) and I use a larger tray to catch the splash from a smaller tray. Unfortuantely, over time the splash tray gets fixer caked onto it. Water takes a good deal of it off with a bit of scrubbing, but there's still the equivalent of sand paper stuck onto my plastic trays.
Anyone know a good, friendly, solvent for this stuff. Maybe something in the under the kitchen sink variety?