Plastimake, a trade name for polycaprolactone, is a moldable plastic that is safe and easy to use in countless applications. Although the name sounds intimidating, it is non-toxic and safe for children. It's so safe, in fact, that it is being looked at for a variety of medical uses, some of which have already received FDA approval. Environmentalists can also feel good about this wonder material, which is 100% biodegradable. Because it can be remolded countless times, a fun figurine or piece of jewelry can simply be remade if you or your child tires of it. If you don't want to sculpt something by hand, Plastimake also sells a molding formula that is softer when warmed so it can be used to create or pushed into a mold. 

Some of the best qualities about it also limit its applications, however. Being biodegradable, the molded plastic only lasts about 10 years- longer if kept indoors. You should also be careful not to use it for any applications that would have it be exposed to high temperatures (60 C or 140 F), as the product would begin to soften at this point. Still, the possibilities are endless.