Silver Plate Mustard Jar Cobalt best Blue Liner

Cobalt blue glass liner in a silver pot. These were done for Mustard and range in age from the 1800's to 1940's when they disappeared. Not sure of the age on this one could be older than i think the silver is marked with an 11 not sure of what that mark means. I think it is a very nice silver plate and the cobalt liner is best a real dark blue. Spoon appears to match the pot and i think is original to the pot itself. These are small items 2 1/2" diameter and 2" tall.