I take 2 medium-ish bristle brushes, mount 1 on a L- bracket and the other with all- thread, connecting it to the L-bracket brush. Install it so it rubs against both sides of the ropes, then run the car up and down on inspection. This usually cleans all the bills up pretty well. Typically I'll just install it in place of where the nylube Oiler is. When done cleaning, I put the oiler back. I can post a picture of the brush assembly on Monday when I'm back at work