If its so tough to remove I would make sure your applying it thin, thin, thin to where your straining your eyes to make sure you coated that area. Also try some Dawn original formula to make sure the surface is squeaky clean before applying your sealant of choice. Zaino recommends using Dawn before using of thier sealants. Of all the stuff available over the counter NF is one of the best imo. Of course never use Dawn for a maintenance wash. Are you applying the NF in circular motions?