Looking at the tarmac pavement down our street you can clearly see where dogs have peed up by the wall (largish circle) and the pee has then trickled down to settle near the kerb (another largish circle) with the stream of pee from one to t'other.
This shows because the pavement is much lighter in colour and looks generally cleaner than the rest.
Which has made me wonder if there is some secret ingredient in dog pee which could be used as a general cleaner.
Or not.
Cheers
Dave R