What is an ash catcher and how often should I empty it?

The ash catcher is a pan, tray, or other receptacle under the firebox of a charcoal grill that is designed to hold the spent ashes. It should be emptied each time you use the grill. However, it takes several hours or even overnight for ashes to cool, so you may want to wait until the next morning. Never put spent ashes in a paper bag or plastic trash can. Often, there are a few live coals or sparks mixed in the ashes and these may set the receptacle on fire. I have seen this happen dozens of times.