Originally Posted by supcom
You can easily clean the rim with a sponge or brush with your favorite bike cleaning solution. The pads can become embedded with abrasive junk. If using a rag or toothbrush doesn't get it, you can remove the pads and rub them lightly on a piece of sandpaper set on a flat surface. Something like 220 grit should do it. Then clean off any residue.
Careful. A lot of people's favorite cleaning solution is WD-40
Use a quick clean-evaporating solvent like alcohol (either isopropanol or ethanol - denatured of course) or acetone.