How do you date vintage medicine bottles?

There are three keys to help with dating most bottles: Side seams: None: bottle may be free blown, in which case it has a very uneven shape and dates before 1860. Or the bottle may have a nice even shape, but was spun in the mold to smooth out the seams; a practice common around 1900-1920.

Are old medicine bottles worth anything?

The Age of the Bottle While not all old bottles are valuable, an older bottle is more likely to be worth more than a newer one. Seams and pontil marks are two of the ways you can determine a bottles age. The pontil mark is the mark at the bottom of the bottle where it was attached to the glass blowers pontil rod.

Why are old bottles blue?

The most popular cobalt-blue color was made by adding cobalt oxide to the glass mixture. The automatic bottling machine came into use in 1903, so cobalt-blue bottles seen most often today were machine-made. Many held medicine, like Bromo-Seltzer or Milk of Magnesia.