I didn't say "dating an oil can" so there shouldn't be any confusion about my social life this time =)
Anyway...I'm trying to learn more ways to determine the age of various oil cans.
First, what year did zip codes come into use? I know it was sometime in the 1960's but don't know exactly what year.
What year did UPC codes come into use? I know this may not be a very reliable way to determine the age of a can since some companies may have begun using them earlier then others.
And finally, concerning Valvoline items, when did the company move from Freedom, PA to Ashland, KY?
Thanks.
