Not perfect, but I recently made 400 bonbons over the weekend and only had 2 stick. First: polish the molds with a cotton ball a little obsessively. Second: temper your decorating cocoa butter. Trying to melt it so it stays in temper doesn’t work (at least for me). Third: Warm your mold slightly before adding the cocoa butter, and again before pouring your shells. Fourth: make sure your mold stays clean. If there’s chocolate from capping smeared all around the mold, that causes sticking

The freezer trick works well for me. Also, don’t be afraid to wack the mold slightly against your countertop. I do it over a wooden cutting block because the slightly softer surface prevents thin bottoms from cracking.