These FT-241 LF rocks have a fail rate somewhere between 40 and 70%. Seeing that myself, dissuaded me from keeping any of them. I believe the only people who might want them are the vehicle militaria collectors. 

I have not myself seen any article on how to bring them back. Maybe two tiny pressure point contacts, that might get some resonant activity, but there's no longterm fix i know of. 

The 'Boatanchors' ham radio group a decade or so back, had a mass dispersal of an FT-241 lot someone had found. Known as "The Great Crystal Caper". I was sobered by the miserable results testing the crystals, and i wrote off keeping any of those series. 

-Hue Miller