Tried it today and it did clean to point but left lots of areas unsatisfactory, I mixed up a second batch making it a lot stronger than before and it finally cleaned some of the stain area, so better than before and if you have no alternative it does improve the area that needs cleaning.
Expectations were not great being sold both as path cleaner plus a moss destroyer
As a moss destroyer it was very good
As a path/patio cleaner I could not see any real effect after application albeit I was not able to jet wash therefore results may have been better
Would still recommend for the moss