a method of temporarily protecting a surface which includes the steps of applying a continuous coating of a masking material to said surface , which masking material comprises , before drying , an aqueous solution or emulsion consisting essentially of a film - forming , carboxylic acid - containing polymer ; coating all or a portion of said surface with a coating compound , said masking material preventing said coating compound from contacting said surface ; and , thereafter , removing said masking material from said surface . preferably said carboxylic acid - containing polymer is an acrylic or methacrylic acid - containing copolymer and is the sole film - forming component of the aqueous solution or emulsion .