Thats what they used!!! The neighbor kids went crazy with these things 2 summers ago and kept throwing them in my backyard...some in the dog pen out back too!! One even landed on my deck! I did file a couple of police reports but never heard anything else about them. These things are NASTY!!! Had a big burn mark on my deck from them. I wondered what they used! If you do see them, absolutely don't pick them up...call and make a police report!!