cleaning strings

[Simon Baxter]

I'm not a piano tuner, but I'd like to be someday, and am spending
some post-college time learning about it. I have a question about
piano strings.

Recently I took apart an old upright I got for free, because I
couldn't afford the moving cost and wanted the parts anyhow, for some
first dabblings in instrument building.

Projects in mind are an Aeolian Harp, and a Hurdy-Gurdy, both which
I've found some step-by-step designs for on-line (though if anyone
knows of any others, I'd love to see them!)

The strings are awfully dirty, my hands are black after handling them
for awhile. I feel like I should clean them, but how and with what?
This is all completely new territory to me... any resources and
suggestions are welcome. Thanks!