AdviceBlogCleaningGardeningPest and diseasePatio Black Spot Remover Patio Black Spot Remover is currently the only product developed specifically to remove those hideous black spots and restore the natural stonework. Patio Black Spot Remover for natural stone will remove black spots from Indian Sandstone, York Stone, Limestone (including Bath and Portland Stone), Purbeck Stone and other Natural Stones. To maintain your garden stonework and stop the return of the black spots, buy and apply our Patio Black Spot Preventer annually. This will kill any black spot spores before they have the chance to germinate and turn into spots. It will also remove green algae without the need to power wash!