[header] How to clean cedar shingles [title] Conduct a soft wash on your roof. [step] A soft wash, also known as a non-pressure wash, is where you take low pressure water and spray down a surface. This is important, as standard high pressure power washes might damage cedar shingles. 
[substeps] Use a 12-volt pump system with pressure of about 60 psi. [title] Scrub the shingles with a bristle brush.