I used the SLEEK boat wash on our GRP hull after a long wet winter, so there was plenty of "green" to deal with. This took it off with a soft brush with minimum effort. Gives a bit of a shine too, even without the use of the wax. Our Marina discourages the use of chemicals which may enter the water, so this was brilliant. A little goes a LONG way and it smells fantastic too. Will certainly be buying more when we run out. Recommended it to a couple of other owners too.