[sdiy] Color Code Jacks

[Scott]

Has anyone color coded their jacks for in/out, or whatever, and if so, could you give me some advice?
I'm thinking I could paint the nuts or washers on the jacks, but don't know how that would hold up.  So far, that's the best I can come up with, as far as how it will look.
Possibly could cut new washers out of plastic or something, but I don't think that would look very professional.  I'd probably use a razor/exacto knife to cut it, and it would leave rough edges, etc.

Thanks for any help.