I don't like chemically cleaning rims or brake pads. Three items:
Scotchbrite pad, flat coarse file or piece of emery cloth, and dental pick. Clean the rim flats with Scotchbrite until all you see is metal without streaks of black rubber from brake pads. Use the pick to take any chips of rim metal or other debris out of the brake pads, then file or sand the glazed areas off of the pads.