I have a late 1920s Sheaffer Lifetime Flat Top in a mottled green-cream-black celluloid. A small chip (about 3/16 X 5/32") had all but broken out of the cap at and slightly beneath the rim. In trying to assess how to repair this very weak area, I inadvertently "helped" the chip the rest of the way out of the cap. This annoyed me enough to get out the superglue and tweezers and just glue the piece back in. I am actually surprised that it seems to be holding but I will need to gently buff out the glue joint and smooth the lip for the repair to be less noticeable. My concern is the strength of the superglue repair so I am hoping that those of you with far more experience might be able to answer a few questions: Would I do harm or could I improve things if I were to use a small amount of MEK on the broken joint from the inside of the cap in hopes of initiating a solvent weld in addition to the glue joint or would the MEK just undo the superglue joint? Was superglue a mistaken way of fixing things or should I just leave well enough alone? Thanks, Cliff