I am completely new to this, I walked around by a river until I found a pepsi bottle that looked like it might be old. I have not cleaned it very well yet. The bottle says Pepsi - Cola on one side, and just Pepsi on the other. Near the bottom of the bottle, it states "Dispose of Properly", the other side near the bottom says "No Refill". On the bottom of the bottle it has an I with a circle around it. Beside that is 141, other markings are AT 14 = 77. I assumed that the 77 was possibly the date meaning 1977. I know this bottle is after the 1950's because of the single dash in between pepsi and cola, but I have not been able to find any other info on this bottle. I know it is not a very old bottle and probably worth very little if anything but I am using it to teach me how to date these bottles. Any help would be greatly appreciated.