Czarbecue
Babbling Farker
Lyfe Tyme, Lone Star Grillz, Gator pits and many others make radiused ash rakes for $25-50. I use one from Lyfe Tyme that came with the pit, then I follow up w/ a small handbroom to get the finer ashes out.
Edit, just realized that wouldn't work on this pit...:doh:
Vacuum or shovel. It's the only way.