Rubbing alcohol works, but so does some soapy water and a Scoth-Brite pad. (Pot scrubbing green pads).
You can sometimes find just the green scouring pad without the sponge. I buy those. Wedge one between the rim and the brake pad and ride for a couple hundred yards. Then switch to the other side of the rim and repeat. Do this to all 4 sidewalls. It'll polish up the rims nicely!
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger