Pesky yellow sweat stains leftover on white shirts after a hard day's work are unsightly and virtually impossible to remove, but aspirin can give you a boost on laundry day and remove the offending stains. Grind up a few aspirin and mix with enough water to form a thick paste; apply to the stains with a toothbrush and then launder in the hottest water possible. The salicylic acid in the aspirin helps make the stain water-soluble.
This same paste can also be used to remove pesky rust stains in the bathroom left behind from razors and metal cans. Let it sit on your tub's ledge or vanity countertop for 10 minutes, then wipe it away. Tough stains might require an additional application.