I have canning directions from a number of universities, Ball, Kerr, Presto, etc., dating back for over 20 years to the present. There have been many changes to the recommendations given by the various sources over the years. Example: pressure canning tomato juice in "Presto Cooker Canner, Directions and Recipes, 1978" lists no requirement for adding lemon juice or other acidification, and a recommended processing time for both pints and quarts is given as 15 lbs - 0 minutes. We've used that recipe over the years with no problems, but have since changed to other processing methods (processing time, acidification, pounds of pressure). It was only until a few years ago that we could find an "approved" method for preparing and canning vegetable tomato juice (V8?), but we've been canning quarts and 1/2 gallon jars of our own "V8", using our own directions which I've published here a number of years ago, for over 30 years! Jeez, did I get the nasty comments after posting that. And, the person that posted that the large canneries monitor the temperatures of each container in a batch, and conduct lab tests on products from each batch has certainly observed canneries other than the 10 or so I've visited. Getting back to recipes for half gallon jar recipes, I know it would be no big deal for a University that routinely conducts food safety testing and publishes "safe" recipes to conduct tests and provide recommendations for canning at least a limited number of recipes they standardize as to type and amount of each ingredient, etc. Heck, I can't believe that a great number of grad students haven't wanted to do just that!

Thanks for your replies -- mildred, you're right -- I guess I assumed people would figure out to click on other pictures, since you can see pics of them on the top right in the preview area...I'll link to an outside pic. And there are *no* markings at all on the bottom, nothing...someone put some little felt circles on them to make them not scratch a shelf, but those were definitely not original. There's also a sticker that looks like it might have been a consignment sticker, same number on each one: MO 016. I get the feeling that was just for consignment, as I said, and has no significance. It struck me that there was no signing on the bottom even though these were obviously somebody's handiwork, with the very rough insides and sand still inside and the uneven pattern on the outside. My question was are these "pretend" jars for tourists from somewhere (I like them, though) or are they something real? And I said on the photo site, I do hope the sand in there isn't someone's funerary ashes! :) Here is a link that might be useful: another view

Thanks for all the tips. I will be drilling into fired clay, no glaze on the bottom of the pots. But they are not absorbant, since they are high fired. Containers are glazed inside and out, with no glaze on the bottoms, which are just high fired clay. I will tape the bottom and drill from there. Since it will be a new job for me, I will do the first one on a piece I can spare if it cracks. Pagan, it is never too late to learn pottery. I have been at it for 22 yrs. I make pottery for use in the tropical fish hobby, but now I can use my many pieces for my growing c&s collection, with appropriate gritty mix now. If my hole drilling works, I will report back with some pics of my success. Thanks again

I suggest you contact the sources listed below,- or ones similar to them- for information. Please note: I am not affiliated with them and am noting them only as examples,of stove experts and restorers .There may be others out there who are equally or even more knowledgeable I did notice, however that the Goid Time Stove Company has some info about Glenwood Stoves and may be able to provide info for you about history, etc. https://goodtimestove.com Please see the photo. Good Time Stoves has a link to all these vintage appliance aficionados and sites at https://goodtimestove.com/faqs/ These experts could be sources of information about your stove. Have you contacted any of them already? Good luck!