Soothie flannel covers are designed to fit the Soothie neck wraps - any of the the flannel, cotton, or lavender neck wraps. The flannel neck wrap covers are best used when you want your Soothie to produce a moist heat. There is also a separate listing for cotton Soothie covers.  
 
To use:
Put the flannel cover on your Soothie neck wrap, then heat in the microwave 2 minutes, depending on the wattage of your microwave.  When heating your Soothie in a cover, you may need to heat it an additional 30 seconds to achieve the moist heat you want, as the heat needs to go through 2 layers of fabric with the cover on.
 
Washing
When you want to wash your Soothie cover, always take the Soothie out of the cover before washing the cover. Do not wash the Soothie itself. It is filled with flax seed and submerging the Soothie in water will ruin it. Be sure to only wash the cover.  You may machine wash the cover in cold water. The fabric is 100% cotton and will shrink in hot water. Hang to dry and iron as needed. If you dry the cover in the dryer, using a cool setting will help prevent it from shrinking. The cover is designed to be a little bit big to allow for a bit of shrinking when washing.
 
Safety Warning 
Do Not Overheat Your Soothie.  Heating more than the recommended time can cause burning of the skin and may cause the Soothie to burn. Because your Soothie will last you many years, it is a good idea to put a mug of water (about 4 ounces or 1/2 a cup of hot water) in the microwave when you heat your Soothie. This will prevent the flax seeds from drying out and prevent your Soothie from burning over the years. Because the microwave will heat the water as well as the Soothie, you may need to increase the heating time by 30 seconds, depending on the wattage of your microwave.