As mine is bright yellow & is not for looking tarty I give zero f*cks about the grit marks up the back but I do wash it every now and then with nikwax. I got a load of the stuff cheap from Wiggle or similar ages ago.
Ta. I just washed it on a quick 30c wash with minimal non-bio to get the shit off the back. Ideally I won't be washing it unless it's completely necessary, but I have got some Nikwax stuff in the garage if need be.
As mine is bright yellow & is not for looking tarty I give zero f*cks about the grit marks up the back but I do wash it every now and then with nikwax. I got a load of the stuff cheap from Wiggle or similar ages ago.