http://www.oiltechnics.co.uk/DrivewayShopHardsurfaces.asp?gclid=COzwucn8_84CFRRmGwoddxsEiA Does what it says on the tin.
Put dry washing powder on and cover it up for a few days and try not to get it wet. After a couple of days wash it off . Sent from my iPhone using Tapatalk
Dilute HCl (Hydrochloric Acid). Sold as concrete cleaner by B&Q last time I picked some up. Try not to spill too much unevenly