Vick's VapoRub info?

[halfdime]

I'm starting to gather quite an assortment of Vick's VapoRub jars; can anyone point to a resource that helps pinpoint dates and interpret other information on the bottom of the jars?

[gleaner1]

I just started keeping the vicks, I must have left over 50 at the dumps thru the years.

[halfdime]

I just love the blue color; naturally, I'd prefer to find something older, but they make a pretty display.