One thing I have recently learned is that Comet seems to clean the same things that the magic eraser cleans (for example - permanent marker from walls, stoves and washing machines, crayon marks on walls, etc.). Now I haven't tried it on everything that the magic easer works on but so far so good. One thing I've also noticed is that they both have the same texture. When the magic eraser begins to break down it feels like wet Comet in your hand, the same chalky residue. Makes me wonder how much they have in common.
So instead of purchasing magic erasers, use Comet and a wet cloth. It's soooo much cheaper and lasts much longer :)