Oh my goodness!! lol I do know that all (or the majority) of my brother's cans are in perfect condition. Not sure which ones he has from Pa, but I will surely tell him!!!
Usually with cans the older the better. Like pre 1962 when they still used the can opener to open them. No pull tabs or easy open ring pull tops before 1962. Of course older cone tops all most always worth something, even in poor condition. There are exceptions though. Like the pull tab Playmate beer can from PA. worth a few hundred. LEON.
WOW!!! I will for sure tell him!! I know he has a lot of beer cans from all around the world. My grandmother was a world traveler, and she always brought him back beer cans to add to his collection!
meds with emphasis on a controlled substance, like heroin, seem to draw a premium over other meds that don't have a controlled substance name on them. At least that has seemed to be true on ebay FYI. I don't think you'll get much more than $20 for the Kaufmann, but that's a total guess on my part. if two someone's are collecting Kaufmann and need that one, there's the possibility of it going better.
Age on the ink? Tough. Anywhere from about 1890 to maybe as late as 1920s, particularly if a British product.