Over at Popular Science, Jim Shaw, proprietor of Uncle Jim's Worm Farm, posted his recipe for Worm Tea, an organic liquid fertilizer and insecticide. The key ingredient is three pounds of castings, also known as worm shit. Shaw writes:
Collect 2 to 3 pounds of castings (or buy them from us). Next, pack them in a porous cloth, such as a burlap bag or even a pillowcase, to make a jumbo tea bag. Then dunk the bag in 2 to 3 gallons of lukewarm water, and soak it overnight. Finally, squeeze the bag; you just brewed your own worm tea.
Spray the Worm Tea on the plants or pour it at the stem. For best results, don't drink it.
"How to brew worm tea" (Popular Science)