While at an NAWCC chapter meeting yesterday I overheard something I wanted a second opinion on. One member told another that he takes old mainsprings that are weak, (sprung), and stretches them out by putting one end in a vice and pulls on the other. He then puts the spring in a 400 degree oven for several hours. The spring is then cooled to air temperature slowly without water or oil. This procedure is supposed to restore the strength of the spring and avoid the cost of replacing it. Is this a recommended procedure for restoring an old spring… or would the proper procedure be to replace it with new? I would appreciate your comments / suggestions. Richard.