A reel to reel tape recorder head demagnetizer might work but who beside me would have one?
Charlie
@Choo Choo Charlie I have one! Actually it was a Radio Shack "Bulk Demagnetizer" if I recall correctly. But samey-samey, no matter what you namey. I will try that next time I run into one of the relays that sticks, and I DO run into them from time to time. My go-to cure so far has been a small piece of masking tape between the relay armature and the"slug." That most often works.
Now that I think about it, I'm guessing the problem may not always be magnetism - since this coil normally runs on AC, it should be 100% demagnetized at all times, as Rob stated above! Perhaps it is just simply something in that hinge mechanism that is causing the armature to stick "up", they are pretty fragile and I oft times see them mangled. Or perhaps there is actually something sticky like old tape residue on the slug or the armature - fresh tape applied on top of the offending sticky part would certainly fix that (temporarily!).
There could even be a stray wire or piece of cat fuzz or even a balled-up piece of 1960's plastic Christmas tree tinsel causing a physical interference!
I never thought of the solution offered by @TrainLarry above. I think I will reserve the "extra weight added to the armature" solution for those times when nothing else works - it sounds viable, but would need some testing IMHO.