The other day I made a bracelet out of an old toothbrush. The white one's plastic is far too thick to bend. The clear kind is rather easy becuase it's not as dense you know, and easier to shape when it's in the boiling water.
When you start out you get all those bristles out, make sure you get those little metal clips out that are holding the bristles together in the holes on the head of the brush. That takes the longest. That and waiting for the water to boil. It took me about an hour to do it all because I had to try out that white one.... still didn't work, threw it away.
Also... make sure you don't do what I did... made it far too small and none of the kids can fit their hands threw it. It looks pretty neat though right?