This is moving so fast but I want to throw this comment out. I think if you all read up on sulfuric acid, you will think this is unlikely to have been used. I don't know a lot about it, not interested in chemistry stuff, but my husband used it and left me with the impression it is pretty dangerous to use and that when companies order it it does have to be accounted for. I don't think it would be on sheets (residue maybe?), it is my impression it eats through sheets, and skin. I know we had a bottle of it in the garage and it had a bunch of warnings, and EPA warnings on it. Just not practical. I had a fit that he had something that dangerous in the garage.