This morning I made two minky covered hot/cold packs for the office. I made the minky covers with Velcro openings so they can be removed and washed. The inside is made with muslin and has rice with a small amount of lavender and mint crystals inside. Microwave for heat (30 seconds to 1 minute depending on microwave wattage) and freeze the inside for cold.
I embroidered the other side with our office name and phone number. I used nylon cutaway stabilizer and a heat removable topping. The size is about 4.5 " x 10". (One bag of 16 oz., inexpensive rice.)