Solar Panels perform to their maximum capacity when they are cleaned regularly.
Installation companies recommend a twice yearly clean to keep your panels running efficiently.
I use only pure, de-ionised water to clean Solar Panels (no chemicals at all)
A soft bristled brush is used to remove dust, dirt and other debris from the glass whilst jets of pure water. The water, as it has no impurities, dries to a spot free finish leaving no marks behind.