what should I use to keep it from sticking. don't want to ruin the molds. I tried sugar, was ok but hard to get off my dark fondant.

thanks

Powdered sugar is one of the only options if you ever want to use your molds for chocolate candy again. 

Use a soft, wide, paintbrush to remove the powder from the black fondant.

Use a second, separate, for-this-use-only, soft, wide paintbrush to gently brush a TEENY TINY ALMOST INVISIBLE amount of Crisco to make the black fondant pieces shiny.  Be aware that once brushed with crisco to become shiny, they will also retain fingerprints if you move or touch or position them.

AI dust the fondant piece with a bit of cornstarch before I press it into the mold. If a complicated mold, I'll put it in the freezer for 5 mins. When I take it out of the mold, I brush it with a clean, soft brush--if it needs it, but they rarely do. I've also spayed pieces with Everclear or vodka.

I rise the mold in hot water and dry the cavities with a cotton ball.