This is a query about the Mauser Manufacturing Company of some 20 years ago on this forum which I thought you might find interesting. If only to show we are consistent in our answers!
In that case the item proved not to be Mauser but the commentator provided useful data about the US company which you might still find interesting.
Historically we have all shied away from giving valuations on this forum because they are frankly too subjective to be of much lasting value.
But, and with the utmost of respect to my esteemed colleague. I think because of the very short time period this company operated, the high quality of American cut glass and the excellent embossing on the sterling lid you might expect a little more.
But to get it I have two suggestions. If I may?
First sell it as a jam jar not a mustard pot. These days both mustard and jam come in their own jars but there is little practical call for condiment jars period. Jam you might find someone who puts up their own getting interested in an admittedly small sample pot.
Secondly find a jam spoon for it. Mauser did make them but I couldn’t locate one quickly. But a contemporary spoon by another maker would be fine. It too should ideally be silver not plate.
BTW, Jeff’s Regency/Vicky mustards with the Cranberry and Bristol glass he shows us all for comparison are lovely too. One probably by the Angel family? Those mustards are coloured glass interiors so you don’t get to look as the brownish yellow paste mustard powder makes you gaze at through clear glass.
Before Bristol glass came along, nearly all mustards were solid silver with glass or gilt interiors to protect from the corrosive damage the paste otherwise inflicts on silver and wood spoons to avoid those rotting not so slowly away if left in the paste.
Jam, on the other hand, looks bright and sparkly through plain cut glass even if that glass did used to have a high lead content which will leach into the jam. But hey, back then if the worst you had to fear was from a beautiful cut glass jam pot, life was pretty good.
CRWW