It's actually pretty easy. There is a slider that opens and closes the vents, which pushes the ash into a removable ash catcher, that you pull off and empty. It comes with 2 coal baskets:
so just grab those and toss the old coals and fill with new ones. Takes me about 2 minutes beforehand to clean up last time's mess and start the new mess. My grate has never seen soap and water...and it's got a nice layer of "flavor".