The best gutter cleaner i have found to work without brushing your arms off is to mix 5 gallons of Bobs f-13 with 5 gallons of glycol ether in a 55 gallon drum and fill the rest of the way up with water.Look out that stuff is great.If you have an older gutter you can cut the mix back a bit.Your getting the best of both worlds when you mix those cleaning agents together.Several products just have the glycol ether in them such as purple power,simple green etc.When you combine the two its like cleaning without even brushing on 70 percent of the gutters.