you can find them at any turn of the century privy even better if they have the name of the town they were manufactured even better if its a small town
Do some research on the towns that had amber cokes in your area and start digging there! We had a coca cola plant here in Lex (still do) and we dig ALOT of amber cokes out of the TOC dumps, cisterns and privies here. You go one town over and won't dig the first one!