Planing can be, as we all know, a sweaty business. Whenever I notice a drop fall on a plane I wipe it away with shavings or a bit of tissue but inevitably bits get missed. This results in surface flecks of the black variant of iron oxide marking the surface of e.g. plane sides and even the brass of lever caps. Although it Looks to be very superficial, I wonder if there is there some sort of treatment wtih which one can remove it? The reason I ask is that I don't like taking even fine sand paper to the metal of a plane. On the other hand, I don't want my planes looking as if I don't take care of them and of course I don't want to risk them suffering any kind of damage in the long run. Any suggestions?