The results: Much better! I left a paste of Mt Dew and baking soda for about an hour, then scrubbed well with a stiff brush. Rinsed the patio off and let it dry--the stains are much better but not totally gone. I plan on using more Mt. Dew this afternoon, letting it sit for longer.
BEFORE: (and this was after much scrubbing with Dawn and power washing!)
AFTER:
Thank you all for the great advice!! Even if it doesnt get any better than this, I can live with it, as there will be several flower pots in this area of the patio.
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SIMPLE DESIGN
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