How to sew a handwarmer

First cut your fabric into a long rectangle

Now, fold the rectangular piece in half, having the inside facing out

Next, sew up all but one side

Now, flip it outside-in

Finally, fill the bag with rice and sew it completely shut so no rice falls out

TIP DO NOT PUT IT IN THE MICROWAVE FOR MORE THAN 1 MINUTE BECAUSE IT WILL BURN THE RICE AND BURST A HOLE IN THE BAG