For those who don't know yet, this from Titebond:
We have had two lot numbering systems for the wood glues. The old one was:
The first digit represents the last digit of the year of manufacture. The second digit is a letter that indicates the month. We use the
letters A through M, excluding the letter I. The third digit is a number. It represents the manufacturing division the product was made
for. The next four numbers represent the internal lot or batch number. That is followed by a decimal point and two numbers which
represent the day of manufacture.
6L12455.23 – This material was manufactured on November 23rd of 2006.
In March of 2009, we switched to the new lot numbering system. The new one is:
The first digit represents A for America (made in), the second digit is the last digit of the year of manufacture, the third and fourth digits
represent the month, the fifth and sixth digits represent the day of the month and the last four digits represent the lot number.
A904270023 – This material was manufactured on April 27, 2009