Guild Wars 2

I still have some of the old transmute crystals.

Do these still work?

Any way to trade them for the new ones?

double click them

Double-click them and they become transmutation charges.

If you double-click on them, instead of initiating the old transmutation, they get flushed into your cache of “charges”. Since the rate of Charge use at all levels, not just 80, is comparable to the Blue Crystals, your Yellow Stones are effectively 1/3rd as useful. Happy patch day!