Patent ID: 8056498

Claim:
An indicator that detects the presence of a chemical residue comprising: a substrate having an upper surface and a lower surface and a first portion and a second portion joined at a fold line, the first portion being smaller in area than the second portion; an adhesive coating the upper surface of at least the second portion of the substrate and contactable with a surface to lift the chemical residue there from, a first reactant adhered to the upper surface of the first portion of the substrate; whereby when the second portion is contacted with a surface containing the chemical residue, the residue adheres to the adhesive and when the first portion is subsequently folded along the fold line so that the upper surfaces of the substrate contact each other, a portion of the adhesive on the second portion remains exposed and the first reactant and chemical residue react with each other to provide the color indicia indicating the presence of the chemical residue.