If you have burned through your charcoal grate, we can guess one of two things is going on. You are either:
Cooking one helluva lot, or;
Burning fires on top of your charcoal grate.
If #1 applies, good for you. We’ll be over for dinner!
If #2 applies, please note that fires burn hottest and best in the bottom of the basin. You do not need to burn atop the charcoal grate for oxygen flow. Trust us on this one.
And in either event, if you need a new grate, here they are!