I have a couople of those microwaveable hot packs that are just wonderful for my back (which went out last week.
They work well, but I want to make one that will go over my sore back muscles and tie around me. Right now I have a long one that fits nicely across my back, but I have to hold both ends to keep it in place. (I can't believe no one thought of this when they made it!). I suppose I could just put ties on the ends of this one, except that it is mostly my SO's hot pack and I don't feel comfortable altering this one.
What do you think they fill these things with? This one smells like popcorn when you microwave it, but nothing has popped
I have heard some people fill them with split peas- seems like it would take a LOT of split peas that would be better off in soup. I could try small gravel, but I don't know how that would microwave. I suppose it would. Can sand be used? That would mold nicely to my back.
Anyone done this before?

What do you think they fill these things with? This one smells like popcorn when you microwave it, but nothing has popped
Anyone done this before?