The dissection trays I have here are the deep enamel dishes half-filled with what I thought was wax - presumably to pin samples into. The science teachers and I agreed that we weren't really fond of the waxy substance, especially as what we dissect here is mostly nice bloody organs, and the "wax" is black, making it impossible to see how well the trays have been cleaned. So, today I put some of the trays in the oven, hoping to melt the "wax" so I could pour it away and clean the trays properly. ...only, I'm not so sure it's wax anymore; it melts, sure, but not like wax. It's really thick and stretchy, and doesn't run nicely out of the trays. It sort of smells a bit like tar. Anyone have any idea what I might be dealing with here?