Picardin is based on the chemical that makes black pepper spicy, which is why it does that if you get it your eyes or mouth. DEET is a toluene derivative which

Picardin is based on the chemical that makes black pepper spicy, which is why it does that if you get it your eyes or mouth. DEET is a toluene derivative which is why it is super effective at melting plastics and doesn’t evaporate quickly It was actually discovered by massive brute force chemical search for repellants