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However, rather than throwing coffee grounds away, they can be reused. Indeed, they have many uses, and such reuse can save you a little money. This article lists a few uses for coffee grounds for the householder and gardener. In all cases, use your common sense and do your own research and investigation to see if using the coffee grounds is making the difference or doing the job that you want them to do.
Compost or mulch
Coffee grounds can be added to compost or used as mulch. They are good for making the soil more acidic, something appreciated by earthworms and plants that thrive in acidic soils. They also add a lot of nitrogen. It's as simple as sprinkling the used grounds over the area of the garden where you'd like richer, more acidic soil. When added to compost, coffee grounds increase the heat of the soil, helping to kill off the weeds (http://blog.epa.gov/blog/2009/02/24/climate-for-action/).
Plants that like acidic soils include: Camellias, azaleas, rhododendrons, blueberries, roses and evergreens. Hydrangea colour can be changed from pink to blue by the addition of coffee grounds (except for white hydrangeas––these remain white). Mushrooms are also said to like growing on coffee grounds. Always check the plant's preferences before adding coffee grounds.
Warning! Professional gardeners have noted that coffee grounds may be too acidic for even acid-loving plants, and some advise mixing a cup of agricultural lime or wood ash to every 10 pounds of coffee grounds intended for the compost (http://www.gardensalive.com/article.asp?ai=793). It's very important to know your soil type before making it more acidic; if the soil is already acidic, you could be doing the plants more harm than good.
Insect and pest repellent
Sprinkle the coffee grounds around vegetable mounds, around ant hills and anywhere else that there are ants, slugs and snails. They don't appreciate the coffee grounds and won't stick around. Allow the grounds to age a little before using for this method.
Sprinkle coffee grounds where you don't want the cat or dog using the garden as a toilet. Mix the grounds with dried orange or other citrus peel to really push the pets away.
Coffee grounds can make things smell better. Place the coffee grounds into a container and put in the refrigerator or cool storage place to soak up bad food odours. This also works in the freezer compartment. Some people advise adding a little vanilla essence (extract) to increase the effectiveness of the grounds.
Boiling coffee grounds before the arrival of visitors will help to make your home smell good and seem more homely.
Another deodorizing method is to dry the grounds in an oven, then keep refrigerated. Every time you have odours on your hands from cooking (for example, fish, garlic, etc.), rub your hands with the cool, dried grounds and the smell should vanish.
Coffee grounds can be used to dye paper, fabric or eggs. Follow the instructions for the item you're dyeing but usually you'll add the ground to hot water to leach out the colour, then dye the item according to the method for the texture wanted.
If you use a fireplace regularly, throw the coffee grounds over the ashes. This will help to stop the ashes from floating everywhere and causing respiratory problems.
Clean your skin
You can use coffee grounds to exfoliate your skin. Rubbing the grounds over facial skin will remove dead skin cells, leaving your skin feeling better.
Clean the house
Given the gritty nature of coffee grounds, they can be used effectively to scour things such as countertops and saucepans. Obviously, test a small area first in case the coffee stains the surface.
Feed the worm farm
Worms will love coffee grounds now and then. Simply sprinkle some in and let them feast. Don't overdo it though; all good things in moderation.
Bait worms can also be kept alive by adding some coffee grounds to their soil.
Groom the pet
If you have a cat or dog, consider using coffee grounds to clean their fur. The coffee grounds should be rubbed through, then brushed out. The fur is said to look shinier and the insect repellent nature of coffee grounds may be good enough to send fleas packing too.
Some people like to rub coffee grounds through a dog's fur after a bath.
Improve your hair
As with grooming the pet's fur, massaging some coffee grounds into your hair when washing it can help to make it shine naturally and also helps to soften it.