cleaning braking surfaces

kiwi_t_hs_b_dog Posts: 83
edited January 2015 in Workshop
Hi all,

Any tips on cleaning braking surfaces? After a recent wet ride, I've been left with small circles of dirt, kind of like dirty water marks on my rear wheel aluminium braking surfaces only. They won't scrub off with water/soap/muc-ff bike cleaner and a brush/sponge. They'll come off if I scratch them off with my nail, but it would take weeks! No idea what they are! Perhaps some sort of surgical spirit would work?

Thoughts very welcome!