Any thoughts on how to clean white exterior plaster?

This is staining from roof runoff on brand new plaster. I already tried a brush application of 10oz. Simple cherry, 2 gallons water and 1/3 gallon SH. didn’t do much. Any thoughts on my next step?


Tried it, no dice.

I ended up using several applications of OneRestore, with marginally good results. I think the builder is just going to have it whitewashed.

Did you try acid?

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One Restore is acid.