We bought from eBay glass fish-shaped plates, manufactured by Arocroc (France) in 1970 or so. The listing had "unused" in the description but that is not certified. How does one kasher glass plates? ...
Some, mainly Ashkenazim, hold that glass dishes must be separated between milk and meat. Some, mainly Sefardim, do not. May the former eat on the latter's glass dishes?
Is one allowed to use the glass cups provided by a hotel (usually in the bathroom) for drinking? Or is there a Kashrus problem?