Fabric

• Because the foot warmer will be repeatedly used in a microwave, a natural fiber a necessary choice for the fabric. It may be tempting to use softer materials, such as fleece, but such sythetic fabrics could catch fire or melt during reheating. For the same reason, cotton thread should be used for sewing the seams. A popular choice for fabric is 100% cotton flannel because it is soft and natural. To prevent hot corn from burning the skin once applied, use two layers of fabric for both sides of the warmer. There is no set size for a foot warmer. For a bag that can double as a back warmer, use 12-inch by 12 -inch squares of fabric. If you prefer a neck warmer, use 24-inch by 6-inch pieces.
  
  

Filler

• Corn will retain heat for about an hour after heating, making it a good choice for filler. For these warmers, use deer corn, also know as feed or field corn. This kind of corn has been naturally cracked during it's harvest and will not burst open during cooking like popcorn. Rice is another option for filler but does not retain heat as long as corn. Essential oils or dried botanical products for added relaxation benefits can be added to corn before sewing the bag closed.
  
  

Alternative Uses

• Tight muscles and achy joints can find relief with the application of a warm, corn-filled bag, while pets and humans alike will enjoy the addition of a warm bag to a cold bed. During summer months, foot warmers can be stored in the freezer for a refreshing cool-down or a safe alternative to an ice pack.