Hi QuiltnNan....recognizing them....honestly...the most telling thing...they are a large sack - kind of like a large pillow case - I think some of them might have had company names printed on the edges... but you also kinda recognize the old fabric that they are made of as being 30's or 40's era fabrics. Other than that - I am sure there are folks on the board who are true collectors and "experts" who would know much more.