I think that the addition of titanium dioxide whitener (or whatever it is they use) to them makes them harder to melt, because every time I'd used them before they got clumpy, grainy, or burned. I usually use the microwave, but I decided to go old-school and do the double-boiler for this batch.
After trying to melt them over a double-boiler for 20 minutes, I put them in the microwave. That only made them get hot and grainy. they weren't melting, and I was afraid that they'd scorch if I kept heating them.
So I put them back over the double-boiler, and went onto facebook to get feedback from other people. Turns out I wasn't alone, and that other people had the same problem with them.
I got some tips, and Elaine Argersinger Spritzer said that she sold them in her store, and sometimes when they sit too long they're hard to work with. She suggested adding some shortening to it (1/2 tsp per pound) and that could help.
I had considered adding shortening before I heard it from her, but I wasn't sure how that would work. Once she suggested it I went ahead and added about 1 Tbsp of Crisco per pound of candy melts. Voila, it melted and after a lot of stirring it smoothed out the candy melts and everything was smooth.
This was the first time that I'd been able to use the white melts without ending up with chunks of unmelted candy in the candy clay. The shortening trick was great, and I'll keep that one in mind for future reference.
Kara Buntin owns A Cake To Remember LLC, custom wedding cakes in Richmond VA