We Clean Solar Panels using a pure water fed pole / brush. It leaves them spot free and does a good job. We use no soap just pure water and soft horse hair brush. We can do Residential and Commercial Solar Panels. Using water from your hose will leave white spots and over time can accumulate a lot of them. Using pure water will not leave those spots. Cleaning your dirty Solar Panels can improve efficiency up to 30% and save you money.