Word has it that microwave ovens are also good for...
drying pets, but I have no firsthand experience to vouch for that.
Speaking of AOL disks, the December issue of Kitplanes magazine has an article about building your own groundplanes and covers for GPS antennas. As one of the 3 test articles, the author used an AOL disk (turns out a CD is roughly 1/4th of the wavelength for GPS signals). It worked very well as a groundplane.