Not long ago, during a tournament, I had set my cue up against a table and started to walk away, when the cue slid down the table and bounced the shaft off a wooden stool. Put a HUGE gouge in the shaft, right down where I normally bridge. It was so annoying!
But I learned something useful that day from a couple of pals who were at the tournament that day, and I figure, there's probably at least one AZB reader who doesn't know this, so I'll share.
To get dings out, take a cloth (I just used a folded over paper towel), get it good and damp, and wrap it around the dinged part of the shaft, and let it sit overnight. The moisture will draw the wood back out, and the ding will mostly, if not completely, vanish. It worked like a charm on my shaft.