Patent ID: 7204890

Claim:
A process for cleaning a solid surface, said process comprising the following operations: (a) forming over the solid surface to be cleaned a liquid coating of a first cleaning liquid that has both of the following properties: the entire first cleaning liquid is a homogeneous liquid when the first cleaning liquid is applied to the solid surface to be cleaned to form said liquid coating thereover; and at least a portion of the first cleaning liquid can be transformed to a continuous coherent solid by a solidification process that does not damage the solid surface to be cleaned; (b) applying to the liquid coating of the first cleaning liquid formed in operation (a) said solidification process, such that said liquid coating is converted to a solid coating; and (c) removing the solid coating that was formed in operation (b) by contacting said solid coating with a second aqueous liquid having a pH value of between 1.0 and 6.1 that dissolves, disperses, or both dissolves and disperses the solid coating during the time of said contacting; wherein in said first cleaning liquid: there is a component of dissolved solid selected from the group consisting of at least partially hydrolyzed poly(vinyl acetate), soluble nylon, poly(vinyl pyrrolidone), and gelatin hydrolyzate; and there is a concentration of at least about 0.8 ppt of a surfactant component of molecules selected from the group consisting of substances that have in each molecule: an imidazoline moiety; and a hydrophobe moiety that satisfies all of the following conditions: it is attached to the carbon atom in said imidazoline moiety that is directly bonded to both nitrogen atoms; it has at least 8 carbon atoms; it contains no atoms other than carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, and halogens; and if it contains any atoms of nitrogen, oxygen, phosphorus, or sulfur, it contains such atoms in a number having a ratio to the number of carbon atoms in said hydrophobe moiety that is not more than about 0.34:1.0.