Some of the dyes used in the early plastics are in fact flourescent, that is, they absorb ultraviolet light and give it back off as visible light of a certain color. This is part of the reason they have that wonderfull luster :)
Somewhere I have a hand saw made out of that pretty stuff...hardly a user, scares the heck out of me, I have a vision of the plastic splitting in half and my hand slamming into the back of the blade, but it sure is purty to look at...