'C' clamps don't last forever. The most common wear happens when the swivel head becomes loose and falls off of the moveable jaw. This doesn't render them useless, but it can be annoying when you have to hold the swivel in place as you set your clamp. There is, however, an option for these old clamps other than throwing them out.
I was looking into wood vises for my island work bench and was surprised at their cost. Even the kits can set you back hundreds of dollars, and still require time and wood to construct. By cannibalizing parts from an old clamp, I was able to create a fully functional woodworkers vise, and by the inclusion of recycled wood, I was able to do it at zero cost.
More importantly, it can be created with only hand tools using a minimal amount of resources, meaning this vise can be put together by anybody, regardless of the size of their workshop.