A polymer is a long chain of small repeating units that link together into a strong, flexible material. When applied to a surface, polymer sealant forms a continuous film that acts as a barrier against corrosive substances. This experiment tests that barrier by spray-painting 20 metal sheets cut from car body panels, then coating half with polymer sealant and leaving the other half unprotected. Over four weeks, ten everyday substances — egg, Clorox cleaner, bird droppings, soy sauce, tap water, sugar water, mouthwash, salad cream, cooking oil, and shaving cream — are spread across matched pairs of sheets. The results show that some corrosives can still damage paint even through the sealant layer, with eggs, Clorox, and shaving cream proving especially harmful.