Sometimes it’s fun to look back at the past and see just how much has changed. A clear example of this is the Gilbert Chemistry set one lady brings into the shop on Pawn Stars. While most of the chemicals were harmless, these sets did contain a few that you definitely wouldn’t see on shelves these days, including potassium permanganate —a poisonous and highly-flammable substance — and ammonium nitrate! In fact, the manual had a recipe for gunpowder! That said, these chemistry sets were well-intended, with the goal of getting kids interested in science. As Rick points out, who knows what type of influence these toy sets had on the future of chemistry. Perhaps these kids went on to study chemical engineering! Find out more about these vintage toys in the following clip.