These Rice Bags are made with 100% cotton. They can be Heated in the microwave or frozen.
To heat in the microwave heat for 3 minutes on high, flip it every 30 seconds to heat the rice bag evenly. If you are heating for a child only heat for 1.5 to 2 minutes. If the rice bag is still to hot for your little one you can let it sit it in the counter for a few minutes until cool enough or put it back in the microwave and leave it in there with the door open.