How do I clean a cement patio?

Liberally spray Wet n'Forget on the dry patio, when no rain is forecast for the day.

Use a garden sprayer, rather than a power sprayer. It will take some months, but you will see a marked difference.

I'd wet down and cover nearby plantings with a plastic tarp, before application.

Plain old white vinegar will work too.

white vinegar to remove kill mold,the stains it leaves Dawn dish soap & baking soda mixed into paste smeared on scrubbed with brush let sit then spritz with vinegar rinse with hot water. wet down any plants around patio and dilute all run off really well as all these ingrdients are also homemade weed killer