You can discard some my way! I've used both System Three and MAS that were two years old, where the resin had crystallised. S-3 told me just to reheat it, and that works fine. With the MAS, I have taken to warming the resin before I mix it because it mixes better.

> My statements may be wrong but I error on the safe side. Personally I use
> about 10 gallons of epoxy a year, I purchase new epoxy each month and
> discard the old.