Flitz Ultimate Crust Remover Patented, revolutionary, X-strength GEL quickly and easily removes even the crustiest of stains, deposits and build-up. Leaves a water-repellant shield. GEL formula has proven more effective than the competitive products. Since Flitz Ultimate Crust Remover uses organic salt, this product can be used indoors or outdoors. Made of an organic salt, it is safer and easier to use than traditional acid cleaners. Organic salt 10 times stronger than vinegar. Safe for use on G