On Sun, 23 Jun 2019 08:48:08 +0100, The Natural Philosopher wrote:

Time and weathering?

detergent and as pressure washer

= accelerated weathering

Trouble with the pressure washer is that it cleans too well and you
have PW the whole area or have clean patch instead of a oily one...

People seem to want single hit instant fixes these days. Yes, you can
spend half a day or longer with various detergents and solvents but
it's lot of effort compared to 15 mins working in some washing up
liquid and leaving it.

--
Cheers
Dave.