In one sentence, describe what the following article is about:

Ball mason jars were produced for many years with the year 1858 printed on them, but this is no indication of the age of jar itself. Rather, 1858 is the year that John Mason was granted a patent for his mason jar design, and the Ball company used this patent year on many jars. This was another patent date that was printed on many mason jars, and that has no bearing on the year of production. In fact, Ball used this patent date on their jars well into the 1930s, so this year cannot be used to accurately date a Ball jar. Many Ball mason jars have a number printed on the bottom of the jar, but this is a mold number that does not indicate the year of production. Rather, the mold number tells you where the jar was positioned on the glass-making machine that was used to produce it. Mold numbers are generally a number between zero and 15, and they'll sometimes have a letter included as well.
Ignore the 1858 patent year. Ignore the 1908 patent date. Ignore the mold number on the jar.