You might have thought it was daggy, but according to the market, your nan's vintage Pyrex is hot. There is currently a single Pyrex casserole dish selling for US$399.95 on eBay and a 33-piece set of Pink Gooseberry Pyrex from the '50s selling for $2,416.41. For real.
It might come as news to you, but Pyrex has never lost its customer base, even after a century of being on the market. On Facebook there are several Pyrex fan pages, including the 17,000 member-strong Pyrex Passion and Pyrex Passion With No Rules (assumingly a rebel faction of the initial group).
One thing is for sure, get over to your nan's and check her cupboards. She could be sitting on a gold mine.