Well, if you are using copper, then the cotton will not seal it against oxidation. Loose fitting cotton on a conductor will probably sound great, but as it ages, the tarnish will adversely affect the sound. Silver, now that may be a different story. I bought some cotton coated silver for upcoming projects because I too believe in theory that it will sound good. I have not yet used it. I had a Lindsay-Geyer interconnect with silk wrapped conductors which sounded great. However, it used a Mu metal wire that does not tarnish.