I'm assuming the PSU was not sleeved by you then.
Buy a starter sleeving kit, that's what I did. You will get acceptable stuff for a small sum of cash; i.e. proper tools, alright heatshrink and black sleeve. For any serious sleeving I'd point towards MDPC-X: http://de.mdpc-x.com/mdpc-sleeve.htm. Nils offers some of the best and highest grade/quality stuff on the market for sleevers. He demands and only offers perfection.