My 2 cents- cleaner wrasses, as a group</em>, do not belong in the aquarium. Sure, there is always someone who has had success feeding them nothing but toilet paper and air, but for every 1 success, I would venture to say there are hundreds, if not thousands, of failures. It is ridiculous to think that a fish that has evolves to eat mucous off of fish will thrive eating anything else. Survive? Possibly. Long term thriving? Never.
Some keys to LONG TERM success would be a very large collection of fish. Otherwise, I would gather to say you will ultimately fail. Unless, of course, you are "lucky" enough to get one of the species as Jaandgc mentioned which is an polyp eater.
Victor, even you did get one that ate other foods, it will not even come close to curing ick. As Fishwhisperer mentioned, if you want a biological aid in cleaning fish, get a neon goby or cleaner shrimp. Because at least these other two can have a chance at surviving long term, and all three are just as unlikely to help with the ick.