Store-bought or homemade silicone molds work well for molding plastic as the plastic releases easily from the silicone. Depending on your mold, you may have to coat it with a mold release or cooking spray.
STEP ONE: Knead the heated pellets.
STEP TWO: Press into a mold while still warm and pliable.
STEP THREE: Once it’s cool, release the shaped plastic from the mold.