If you've been working with stained glass for any length of time, you know what flux can do to your favorite tools.
Flux corroded tools look oxidized and don't move freely, sometimes not at all. You don't want to buy new tools every time this happens.
I did a little research (so you wouldn't have to) and this is what worked for me.
1. Put your tools in a plastic container and fill it with white vinegar until it covers the tools.
2. Let it sit over night - or longer if the oxidization is bad.
3. Blot dry and then soak the hinges thoroughly with WD-40.
4. Work the hinges until they move freely.
5. Repeat steps 1- 4 if necessary.
Finally spray the metal with WD-40 and buff the metal cleaning off as much of the "gunk" as you can.
I had to soak mine in vinegar twice before they would move freely, but it was better than buying new tools.