Can anyone help with this problem? I have Sun Rhyno rims and Kool Stop salmon-coloured brake shoes, which give awesome stopping power when wet and clean, but in wet conditions soon get contaminated with a grey filth which might be from the road but might be from the shoes themselves. When the rims and shoes are wet and contaminated, the first few turns of the wheels has little or no braking effect (and there is a sinister pasty grinding sound), then the brakes start to work, but not well compared with their wet-weather performance when clean. The shortest riding distance from clean to filthy is 4 miles in drizzle on city roads, which is less then my ride to work.
I would be really grateful for ideas about how to prevent the contamination, or how to remove it during a ride without carrying acres of wet wipes or a load of water and a brush.