I was house-cleaning today and dug out a steel GI canteen. The maker is S.M.C.O. and the date is "194(can't tell for sure but could be a '5'). The canteen itself is in pretty good shape. The little cork gasket in the cap has crumbled away. Is there a relatively simple way to replace the cork or a place that sells replacement caps that someone could point me to? Google bring up gazillions of places that sell caps for the current plastic canteens.