I am no expert on this watch however I would suggest that the 'glass' as you call it was probably acrylic originally, mineral glass was very uncommon in this era of watch making so don't throw it out. As far as cleaning the dial DO NOT attempt this yourself you may ruin it. I would leave it as is to be honest its part of the patina of the dial and IMHO looks great as is. Just my 2 cents worth.

: Hi

: An update on the glass - I ordered a 31.2mm domed mineral glass,
: and it fits perfectly.

: Just wondering if anyone has any thoughts on the watch itself.
: Looking at the info on this site, it appears to be:

: Reference 347
: Movement Valjoux 22
: Movement serial number 705149 seems about right?
: Case number 64861 seems about right too?
: Any idea of the age? Maybe 1940's?

: Thanks
: Rog.