Look for the 3-L logo. The Ball logo has remained relatively standard since the first script logo was introduced, but there have been a number of small variations that can be used to date the jar. The 3-L logo, for instance, was only used between 1900 and 1910.

How can you tell what year a Ball jar is?

Some helpful notes to keep in mind:Not every jar has their manufacture date on the glass, but most have the patent date. There will be a large number on the bottom of your jar. These charts tell you the approximate decade in which your Ball jar was made.More items •9 Aug 2017