Try to give it a sniff,If it smells like beer or vinegar,it was probably a beerball,if it smells like poop,maybe a colostomy bag of sorts?Beerballs are usually dark tinted amber& without any bags inside,I have not seen a clear beerball!I would go with Nighthikers choice-Some type of methlab parts or such!

Sure hope it wasn't a shake and bake, single pot, meth cook lab......

The beer balls are amber to keep out the light. Light damages beer. The mylar bag would do the same thing as the amber beer ball. Just as a general rule of thumb though...don't smell things found in the dumpster.