PRODUCT FEATURES Oxidation Layer Removal: Specifically designed to target and eliminate the oxidation layer of paint, the root cause of those stubborn black streaks in your gutters. Dilution Versatility: F-13 is your cost-effective solution. While many butyl-based products lose their strength rapidly when diluted with water, F-13 remains highly effective even at dilution ratios as high as 50-1. For more stubborn stains, you can safely use F-13 at dilution ratios as low as 5-1, ensuring you have the right strength for every cleaning task. Economical Usage: With F-13, you get more bang for your buck. Typically, a 20-1 dilution is sufficient to remove oxidation with minimal effort. This makes F-13 an extremely economical choice, saving you time and money while achieving superior results. Efficient and Effective: F-13 is your trusty companion in the battle against gutter stains. With a little agitation, it works swiftly, eradicating oxidation and restoring the pristine appearance of your gutters. Get a 70mm 5 gallon cap wrench here! Reviews Featured Products The Gutter Tool $23.95 Out of stock GP Gutter Hook $12.88 Add to Cart F-10 Percarbonate Cleaner $11.07 Choose Options F-8 Neutralizer / Brightener $11.34 Choose Options