I'm working on a 1998 Ford Contour with manual windows that has partially broken crank handles on both sides in front. The knob you grip while rotating the handles has broken off, which makes it annoying to roll the windows down or up. What's the procedure for removing and replacing the handles? What's the part number for a replacement handle?
There is a small clip behind the handle that retains it to the regulator shaft.You have several options to repair it. The first is to pry on the handle until you destroy the clip and replace it when you install the new handle. Using this method generally results in a damaged door panel also. Any auto parts store sells a door panel tool for under 10 bucks that removes the clip without damage to the door panel. The third option is to locate a window crank knob. Most auto parts stores have a display rack that has items from a company called "HELP" it is a division of Dorman. They specialize in small items that frequently break or get lost. You may be able to find a knob that can be installed without taking off the handle.
There is a clip holding the handle on the shaft. You can see it if you gently pry the opening between the base of the handle shaft and the trim piece attached to the door. I've seen reports of removing it with a knitting needle or working a shop rag into the gap. I use a wire coat hanger. A thin piece of metal would be ideal, such as the tool mikes mentioned in his answer. If you're trying to pull the clip off, there is a loop on the opposite site from the handle shaft. If you're trying to push it off with something, you want the other side.
Once the clip is off, the handle comes right off the shaft. As for a replacement part, I've seen the handles at Autozone that mikes mentioned. They'd probably work just fine, but I went to the parts department at a Ford dealer and had them order two handles. The part I got was F8RZ-5423342-AAB. If I plug that into the Team Ford Parts Online site, that comes back as a crank handle for a 2000 Contour. It's a very close match, I attribute the slight difference to sun fading on the old part. The color I got was grey, the Team Ford listing says 'order by color'. Another source would be a "do it yourself" junkyard such as Pick 'n Pull.
As for installing a new handle, just slide the handle onto the shaft with clip in place. Rotate the handle to line up with the trim piece on the door and push gently. With a little pressure, the clip will slide into place and hold the handle on.
If you could find just the knob somewhere, it looks like it's possible to remove it from the handle, but I think it would be tricky without taking the handle off first. I think you would need to push what was left of the old one off from the back.