Angie's List Message Boards : Angies List Forums

I let several black garbage bags (full of grass, twigs, leaves, and stuff) sit on my flat cement garage floor for perhaps several months.  When I arrived to check on it, and move the bags to the curb, I found black gooey black stain-like stuff on the garage floor under the bags.  I imagine that chlorophyll (decayed plant matter) and ...