Is a clean roof a happy roof?

[Tinkerin_wit_tools]

Was just curious, but after a couple of years, my shingles don't have that nice color any more. I know that weather, temperature extremes, and time can do this, but can I use my pressure washer to clean the shingles? Since it is 3000 psi, I know to use a lower pressure nozzle, but is there a solution I can mix up with the water to use on my shingles to clean and protect them?

[Patriotic]

Shingle color

I would NOT do that. Shingle color fades as well as the granules which have the color come loose and fall into the gutter from rain, heat, walking on the roof and just aging. Pressure washing, I think, will just encourage the loss of more granules and you'll have even less color.