Even smokeless fire pits leave some ashes beyond. It’s important to remove ashes from a fire pit when it’s nearing an inch in height. The problem with leaving ashes is that they can cause damage to your fire pit over time. The good news is that there’s a lot that you can do with ashes as opposed to merely throwing them away. Ashes can be added to both compost and soil, as they supply magnesium, calcium, and other minerals. Ashes are also used to forward away insects.