Use a butter knife to pry it off. Insert the blade of the knife between the clip and the plastic below it and then use a gentle upward prying motion, kind of like using a bottle opener. Use the side, not the tip of the blade.
push it to the side where the opening will slide out.
I don't get that answer. http://www.rd.com/content/openContent.do?contentId=17901 has some good advice. I like their suggestion you do this when the hardware store is open since you'll probably be making a couple of trips for things you don't have.
I just replaced my faucet. First, I sprayed the nut holding faucet in sink from underneath with WD-40. (Don't let it drip in your eyes.) I turned off the water. Then, since I was going to throw the old faucet away, from under sink, I bent the copper water tubes back and forth so they broke off as high as possible (above nut holding faucet to sink). I undid flexible tubing so it could be pulled up as high as possible from sink end to get it out of the way, too. Then there was room enough to grab the nut and turn it counterclockise. I used a basin wrench, but small adjustable wrench or vice-grips probably would have worked, too. I had to grab the large washer and nut together and turn them at the same time at first.
I also had problems with that answer. I was trying to replace just the sprayer head - not the entire hose - on my kitchen sink when the confounded retaining clip completely halted progress. Every article I read said something along the lines of "merely slide the clip off," or "this is so easy, even a caveman can do it." Perhaps they were working with a type of sprayer head assembly not available in my part of the world????
I ended up prying the darn thing out with one of the pointy awl-like attachments on my leatherman. I couldn't get needle-nosed pliers to grab it, and a butter knife (a suggestion from another website) wasn't even a possibility. It took at least a half hour, (one or two bloody knuckles and some choice swear words) and I gouged the heck out of the old nut and took a fair bit of plastic off the hose before I could get it off. However, when I put the new sprayer on - everything seemed to work and there are no leaks.
I subsequently tarred and feathered the old retaining clip when I was finished.
I was struggling with the same issue. I used a steak knife, which has a thin, pointed tip, and pried that under the back edge of the clip. That gave me the ability to get under the clip, and it slipped off with no problem.