Most of the toys on the marketplace today are made from sort of vinyl. Why? Because it is a byproduct of petroleum and therefore available in abundance. You can pick out vinyl by its strong plastic like, or sometimes, burnt smoky odor. Any of the super soft materials like jelly or the pink flesh-like feeling ones are all vinyl based.
The issue that many toy afficianados have with vinyls is the toxic plasticizers that are required to make it soft. Since the lining of your rectum is designed to absorb, anything that you insert there will run the risk of entering into your bloodstream, the danger of which is enhanced even more if you’re wearing plugs for long periods at a time.
Because vinyl is a heat vulcanized material any heat it is subjected to in cleaning and sterilizing acts to slowly breakdown the material itself and release more of the plasticizer. If you’ve ever had a toy get gummy, soft, brittle or melt other toys it touches this is why. Eventually cleaning them becomes impossible or they just end up breaking or too sticky to use.
Never remelt vinyl and try to recast it or try to smooth cuts with heat as the smoke contains dioxin along with other harmful chemicals.