We will belting hundreds of vintage flour, corn meal, etc. paper bags over the next month or so.  They are all the PROOF bags from the bag printing and manufacturing company.  Typically, the the bottoms have yet to be glued together and they bear a rubber stamp indicating: FIRM NAME, MATERIAL, BAG SIZE, DATE, O.K BY, with blank lines after each. The blanks are filled in by the company and there are approval signatures.  At times, there are notes indicating needed changes.  We are ab le to date the bags accurately by the approvals.

PROOF BAGS  are pretty much non existent in the market.  We have never found one for sale.