Oh my god! I just tried to heat my Pop's Rosin in the microwave because it was not rubbing onto the bow hair properly. I turned it on high for a few seconds and WHAM! there were sparks and a flash of light in the microwave! I turned it off right away, part of the rosin case was singed black ... Apparently the waves had reflected off the metallic sticker on the side, because I tried it again without the case and nothing happened ... anyone else had this kind of experience? Certainly gives a new sense to the name Pops Rosin!