I haven't found any listing of the different canning companies that produced quarts. Here is a link to the list of Continental Can Co. cities and plant numbers: https://www.therustybunch.com/phpBB3/viewtopic.php?t=17844#p383264 that you might find interesting. Any quarts that you find with CCC and a number following is the plant number for CCC which some people mistake for a date number. Good luck with your hunt. Maybe this should be in the FAQ forum with other lists. Cheers, Don.