When I was 15 and working as a short order cook/dishwasher in a restaurant I once poured an entire bottle of liquid dish soap into a commercial dish-washer (restaurant).

Talk about stupid. Took me hours to clear out the room full of suds.

It was kind of neat though to watch the foam pour out of the edges of the machinery.

Another time some friends of mine and I put a can of baked beans into a campfire. It took about 30 minutes to do anything but eventually the can exploded like a cannon, blew the fire apart (and out) and the only thing we found was the wrapper and one bean. Never found the can. Good thing we were hiding behind an overturned picnic table because the risk of shrapnel injury was pretty huge.