Here are two clever way to reuse coffee grounds: Use damp coffee grounds as an abrasive cleanser for your cast-iron pans. The natural oils in coffee will help break up stubborn stains or burnt-on food without ruining the natural nonstick surface of the pans. Just scrub with a sponge and wipe with a damp cloth. And the next time you’re cleaning the fireplace of white ash, sprinkle damp coffee grounds on top before scooping away. The grounds will help settle the ash so it’s easier and cleaner to scoop up. When you’re done, you can toss both the grounds and ash into your compost bin in the backyard.