The answer to 'how to clean architectural shingles' is to use a soft-bristle brush and a mild detergent solution. Start by gently scrubbing the shingles to remove any dirt, moss, or other debris. Rinse the shingles thoroughly with a garden hose to wash away the detergent. Be careful not to use high-pressure water, as this can damage the shingles. It's important to clean architectural shingles regularly, typically once or twice a year, to maintain their appearance and extend their lifespan.
If the shingles have significant buildup or damage, it's best to consult a professional roofing contractor for a more thorough cleaning or repair.