I have had this bottle for a probably 20 years or so. One day while walking through the woods near my parents house we came across what appeared to be an old homes or buildings. All that was left were the foundations in the ground but there were several cobalt bottles as well as other types of glass jars buried in the ground. We took a few bottles the 1st time we went but over time we picked up quite a collection of these bottles, unfortunately my parents considered them all pretty much junk and this is the only one I still have. Just wondering if anyone had any info on it or if it had any value. I figured it was from the 1920's-1950's. It has an M on the bottom of the jar and measures a little over 3 inches tall.