One thing to note is if the cables have a teflon jacket (like the AudioMagic Hyperconductors), nothing is likely to stick/stay on. A more involved, but longer lasting, solution would be to remove one of the XLR ends from each cable, cover the cable in black techflex, and then re-solder the XLR connector back on. A bit of effort involved, but you'll have a very nice set of cables when you're done.