I've hear of both ways. If I had a hard crud ring build up, I would use a wire brush with a damp patch wrapped around that. I would then swab the barrel hoping the combination of the bristles and the wet patch would remove the crud better.

In my cases, I seldom have a hard crud build up because I shoot mostly Goex. So I use a cleaning/loading jag and damp patch followed by a couple of dry ones..

All you need is a damp patch. If you use a real wet patch and have any doubt that excessive moisture might have gotten into the breech plug, pop a 209 primer or two before you reload. Also I like to swab with an open action. That way if things are too wet you can see evidence of this by moisture coming through the breech. Then I push a dry patch down there and pop a couple primers to make sure all the moisture is out of these.