DIY Cable: Cotton

Okay, so I've mulls over creating own cables but, for the time being, I probably won't. However, I'd like to accumulate some information. One of the things I have read recently is that cotton makes a good insulator/shield for cabling (dialectic?). I've seen this on speaker cables, but not interconnects. Why? Or have I just missed those?

Secondly, has anyone ever experimented with a way to 'add' a cotton insulation to a run of wire if it didn't have one already? I've considered getting take with a cotton fabric backing, but my guess is that either attacking it directly to the wires (rather than free floating) or adding an adhesive are both likely to be bad ideas. Otoh, what the hell do I know.... That's why I'm here! :)

Thanks! Aaron