I wish I could Photoshop out the ash

We're still sitting on our thumbs in Barcelona, not at all sure what to do or how we might get home or when (Tuesday 7am? overnight ferry? never?) and I was thinking about the really cool tools in Photoshop CS5. I often wish that life had Ctrl-Z - when I drop the plate on the tiled floor, when a cat knocks my potato into a dust bunny - and now I wish I could just select the ash cloud with simple seelction and use the content-aware fill...