harold,
drop a little dishwashin soap on your finger, spread it around the MM sheet/pad and rub it good between your palms. that gets most of the stuff off, but not 100% of it. however, the little left over doesn't seem to affect the sheets at all.
you can also put them in a garment bag and put them in the washing machine. i just think this takes way longer for the same effect as hand washing them.
make sure you use cold water either way and air dry them as the dryer will melt them.