I was somewhat surprised to find out that this is a common problem. One fellow says he repacks his bag 3 to 4 times a year!
I see the advice repeated to not store the bag on its hanger, but to take it down and lay it on its side when not in use. Easier said than done most definitely.
Rags are indeed the main stuffing. Some people say to blend sand with the rags, but most say to put the sand in bags, just like mine had, and keep them in the center of the packing. Many people get rid of the sand bags altogether, or put them at the bottom and sometimes also the top of the bag only. Some people use a mix of sand and sawdust.
Don't leave a heavy bag hanging outdoors. At least store it upside down.
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