(link) REUSE & CONSERVE WATER ~ The next time you boil eggs (hard boiled eggs, deviled eggs), save the water and pour it onto the soil (NOT plants!) for your garden and houseplants. The water becomes enriched with calcium from the boiled eggs shells.
Aspirin is a remedy for fungal plant problems (black spot, powdery mildew, and rust are a terrible trio of fungi). Dissolve two uncoated aspirin tablets milligrams each) in 1 quart of water and use as a foliar spray to thwart these diseases.