I found tons of suggestions on cleaning tokens around here, but couldn't decide which one would be the best. An experiment was in order!
Here are my results from least to most effective:
Whiskey, Tobasco, Beer, Listerine, Hydrogen Peroxide, Ketchup, Vinegar, Diet Coke, Coke, Lime, Lemon, Kaboom, Taco Bell Fire Sauce, Brass Cleaner
If you want to see in detail why I chose these cleaning products, how I came to my results, and a possibly decent attempt at humor, check out
The Great Token Cleaning Experiment (rated PG13).