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- 3,957
- Location
- Gloucestershire
I have a customer who has sills like the ones in the picture. The picture is taken from Google street view and its clearly a long time since they've been down that road as they are now black with algae and lichen. I don't fancy pressure washing them as they look like some type of sandstone, also they are first floor windows so that would be effort in itself! What would you guys use to clear it off?