Abstract: Disclosed is a method for customizing a thermoplastic resin in which a thermoplastic resin body is at least partially coated with a thermoplastic coating composition comprising an additive component and a polymeric component. The thermoplastic resin body is at a temperature that is above the onset temperature of the melt processing range of the coating composition. After the coating is applied, the resin body is cooled to solidify the coating composition. Customized thermoplastic resins may be produced more efficiently using the present method than by conventional methods. The customized thermoplastic resins produced according to the invention may be heated to above the onset temperature of the melt processing range of the resin body, mixed to form a substantially uniform mixture and formed into an article.