Disposable biodegradable empty tea bags. There's a pocket and a large flap, and you simply put a spoon or two of tea into the pocket and wrap the flap over it and put it in your mug.
You can now make loose tea with NO mess, NO hassle, and in about 15 seconds you've filled your tea bag and dropped it in your mug. Pour in hot water. When you're done steeping, you pull it back out and put it in your compost (or set it aside for a second steeping).
There are a few brands of empty tea bags on the market, but this is a good brand because they are over-sized, which allows a tea like an oolong or other full-leaf tea enough room to unfurl and steep properly. The filters are bleached, but it is a non-chlorine solution -- the filters are all natural and made from nuetral-tasting hemp and wood fibers.
You get 100 filters in each box.