According to Wikipedia, this was a known problem in the early part of the last century. But by the 1950's it was primarily resolved. Clearly it still happens on occasion. It says some modelers soak their parts in vinegar and then paint them and claim it helps. How often do couplers or parts crumble away? Like I said earlier, I've only experienced it once and I've got 100s of cars. And is there any preventative maintenance like vinegar that would help?