I'm not sure if anyone else does this but wanted to share...after my last cake I had all of these tiny bits of different colored fondant leftover and it was driving me crazy. I hate throwing things out. So, I took a recipe for chocolate fondant and measured out half of the liquid ingredients plus the cocoa into my mixer and threw all of those fondant pieces in and mixed it with my dough hook. Then I kneaded in by hand some powdered sugar and I got a terrific, full batch of chocolate fondant with no color pieces showing.
Brilliant! I usually just wrap and freeze my fondant leftovers and they seem to always come in handy.