Spray the mold with a food-grade silicone or mold-release spray. Mix the resin and the hardener according to the manufacturer's instructions.
Working quickly, fill the mold halfway with resin. Now is the time to add an object or dye. If the object is made from an organic material, it should be sealed with a decoupage medium first. Brush the object with the resin, and using tweezers, carefully place it face down in the resin. Fill the rest of the mold with resin, and stop just before hitting the top. If coloring, mix the dye with the remaining resin before filling the mold. If bubbles have formed, quickly pass a hair dryer over the surface. Be careful, as the heat can warp the plastic mold.
Resin cures best between 70 and 85 F. Pieces that are less than a half-inch thick cure in 72 hours. Once cured, twist or push the mold to release the resin.
With a 1/16-inch drill bit, drill a hole into the resin piece, and smooth the hole with a bead reamer. Use the pendant on a necklace or as a bracelet charm.