If it's rust coming through because the chrome has gone in places, then it is possible to get it off with a brush and/or metal polish such as Peek. However, it will come back, and wire brushing often has the effect of getting under the chrome plate around the spots and lifting more off.
Out of interest, what make/model of razor(s) are you looking at? A lot of old e.g. Gillettes are chromed brass, and whilst damaged chrome on these is unsightly and not a good thing, it's not as bad as chrome on steel. Another one to watch out for is chromed Zamak (old Merkurs, for example, and others). I have a couple of these, bought new, and over time, the chrome has deteriorated and the Zamak has turned to powder/dust. Both these conditions can be mistaken for a rust (i.e. steel razor) problem, especially if the information is from some not especially good or clear photographs.
My own view is that it is generally best to avoid razors that have any amount of surface damage, particularly on the head and especially the top cap. A bit on the handle might just be acceptable, but if you plan to use it, it's likely that the condition will get worse with use.
Of course, it's possible to have razors re-chromed, but it's not cheap and there seems to be a shortage of people doing razor restoration these days. It's best reserved for super-special finds, if then. I'd suggest holding out until something in good or even very good condition shows up.