Regularly clean the countertop Regularly clean the countertop with the use of dish soap or detergent liquid and water for eliminating everyday grime, dirt, and food residue. Once you have completed this step then dry the countertop with a soft and clean cloth, for preventing a watermark. For removing stubborn dirt using an ammonia-based spray cleaner. Regularly Polish Countertop The Corian countertops come with a matte finish, gloss, and semi-gloss finish so that you can easily maintain this countertop.