Patent 4077 - S6-E16
Corrected entry: Hawkeye and B.J. buy Margaret a new ring in place of the one mistakenly thrown out by Klinger. The peddler says, "Cheap setting, miracle glue". Cyanoacrylate glues were first discovered during WWII but were not commercially developed, as it was thought their quality of sticking to everything was a nuisance. It was rediscovered during the 50s but was not sold until 1958, five years after the end of the war. The second mistake is on this site: the episode was not called "Patient 4077," but "Patent 4077."
Correction: This is not a mistake - he is using the word 'miracle' as a description, not a name. Americans call Miracle Glue 'Crazy Glue' (in the UK we call it Super Glue). It probably isn't cyanoacrylate he is talking about. The second 'error' isn't even a film/television error in the first place.