While shoveling things off the workbench, I encountered a old wooden ruler with brass-colored metal edges, one of which had popped out of its groove. No wonder: the poor thing was bent into an arc the hard way. I have no idea how that happened, honest.
Anyhow, I figured I could fix it with the same technique I apply to straighten copper wire: grab one end in the bench vise, the other in a Vise-Grip, and whack the pliers with a hammer to stretch the wire a percent or two. So I did that and failed completely: the metal strip is actually copper / brass plating on steel.
But it was straight enough to tuck back into the groove, where friction seems to be holding it in place, and all is well.
(If I’d found it before I put a dot of epoxy into the sunglasses hinge, I’d have dabbed some dots along the groove and secured it in place forever. No such luck… the workbench is really buried this time.)