[TomCrowther]

Hello All.
I have not cleaned something like this before and would appreciate any help or advice. Customer has 100 storage units, nicely painted last year but suffering from dirty splashes caused by passing cars and "bouncing rain".
They have tried pressure washing- looks ok till it dries.
Various chemicals and wfp- as above.
I said I would return with a couple of different chemicals and see if we can help.
I think the problem may be the chalky/Sandy stones that were the ground surface until the tarmac went down.  Customer wants a very clean site. What do you think may work.
Because they are storage units, he isn't too keen on pressure washing in case water ingress damages the contents.

[chris scott]

Any pictures?

[TomCrowther]

No pics but they are painted black and majority if the stains are light brown from the stones ground surface.