Tree sap on Crab Orchard flagstone
I just had two Bradford Pear trees taken out, and now reddish-brown sap stains are all over my Crab Orchard flagstone patio and concrete driveway. I tried Dawn, then baking soda and hot water, with lots of scrubbing, but the stains aren't budging. The patio is only two months old and hasn't been sealed yet. Do you have any advice or recommendations for removing these awful stains? Thanks so much!