Plants with lots of green foliage love coffee grounds as fertilizer. Even if you don't have plants to use them on you would be better off sprinkling them through your lawn instead of having them dumped in a land fill. You can also use them to repel ants and feed worms. You can dye furniture scratches, paper, or cloth. You can also use them for a deodorizer, just set them out in a problem area.
Acid loving plants benefit from used coffee grounds. Roses, blueberries, azaleas... Also you can use grounds for staining wood or paper to give it that aged look. It keeps ants away; just sprinkle them right on ant hills. Good for your lawns, especially for those "bald spots".~~~~~~Relieve a hangover. Drink a couple of cups of Coffee. Coffee acts as a vasoconstrictor, reducing the swelling of blood vessels that causes headache.
Spread grass seed or fertilizer. Punch holes in the bottom of an empty can of Coffee, fill with grass seed or fertilizer, cover with the plastic lid, and shake the can as you walk through your garden.
Transport live fishing bait. Keep worms in a Coffee can filled with moist coffee grounds.
Keep toilet paper waterproof while camping. Carry a roll of toilet paper inside an empty Coffee can.
Protect baby tomato plants. Remove the top and bottom from Coffee cans, place a can over each plant, and step on the can toset firmly in the soil. Remove cans when plants are a few weeks old.
Grow better melons. Raise melons off the ground by resting them on top of upside-down empty Coffee cans pushed into the soil. The metal cans accumulate heat, making the fruit ripen earlier and repelling insects.
summary
1) First of all, they can be used as a fertilizer for any plant, whether it's a house plant or an outdoor plant. You can either make your own liquid fertilizer by boiling what's left in them and using the liquid or by just sprinkling them around the plants (not on them) and then watering.
2) Since they attract worms, you can mix them with soil or manure and make yourself a mini worm farm. This is a great idea if you like fishing.
3) They can be boiled and then the liquid can be used as a stain. The stain can be used on wood (to touch up scratches or for an entire item), baskets, paper (to make a parchment-looking stationary), or even a tie-dyed shirt.
4) They can be dried in the oven and put in used pantyhose and used as a deoderizer in closets, cars, or your refrigerator.
5) They can be used as a bug repellent (especially ants) either around plants or around an entire house by spreading them around the perimeter.
6) They can be used as a deodorizing mud facial mask or as an exfoliator for the entire body.