Patent ID: 6974605

Claim:
A method for enabling unwanted substances such as graffiti to be removed once applied to protected substrates, the method comprising: identifying a substrate protected from unwanted substances such as graffiti with a clear, two layer coating including a saturated, aliphatic urethane protective topcoat over a polymerized primer layer on the substrate: wherein the primer layer is formed on the substrate from a primer layer composition obtained by mixing an acrylic copolymer and water, wherein the topcoat is formed on the primer layer under ambient conditions from a topcoat composition obtained by mixing a polyol and an aliphatic polyisocyanate; wherein the primer layer prevents the topcoat from causing the substrate to appear substantially darkened after the topcoat has hardened on the primer layer compared to the appearance of the substrate before application of the two layer coating; and applying a cleaner to remove any unwanted substances such as graffiti from the topcoat after unwanted substances are applied onto the topcoat; wherein the unwanted substances are removed from the topcoat without the topcoat being substantially degraded by the cleaner.