There are a few ways to clean wax off of an outside of a Scentsy warmer. The most common way is to use a vacuum cleaner with the hose attachment. Another way is to use a bucket and pour water onto the wax. Then, use a cloth or paper towel to rub the water onto the wax. Finally, use a heat gun to heat up the water and then add it to the cloth or paper towel and rub it onto the wax.