The invention relates to a method for producing thermoplastic molding materials based on acrylonitrile-butadiene-styrene copolymers (ABS) having improved surface properties, in particular improved resistance of the surface quality to storage in a warm, humid environment, and having a reduced content of residual monomers. The invention further relates to the use of a fluid bed dryer and/or a flash dryer in the production of thermoplastic ABS molding materials in order to improve the surface quality. The invention further relates to the use of a fluid bed dryer and/or a flash dryer in the production of thermoplastic ABS molding materials having a reduced content of residual monomers. The invention further relates to ABS molding materials that can be produced by means of the method according to the invention and to molded parts (e.g., molded bodies, films, and coatings) that can be produced from the thermoplastic molding materials according to the invention.