Each cracking sound reminded me of taking the lid off a jamjar, while the process as a whole was like splitting open a wooden packing case, plank by plank.
It turned out that 1) women were stretching them to seal preserves because there were no jamjar tops, 2) office workers used them as glue spreaders, and 3) "private manufacturers .
Jean Kerr, author of many successful novels and plays, says that she reads every soup-can and jamjar label in her kitchen before settling down to her typewriter.