Yah, its pretty clear from those pictures its not the leaf but the resulting compressed pulp, which looks pretty similar to the stuff I spray off my driveway ev

Yah, its pretty clear from those pictures its not the leaf but the resulting compressed pulp, which looks pretty similar to the stuff I spray off my driveway every year with a 3200psi pressure washer. That i largly a mix of leaf/etc with black mold, which actually grows into the concrete pores. Which makes me wonder why no one bothered to try something like that, are pressure washers common in the UK? Mine is hardly the highest PSI, and it frequently needs to be turned down because at that pressure it can actually etch soft concrete. And at 2.5GPM its not using a lot of water either.