Handling duplicate tags?

I have the awesome extension from Deano (Deanos Tools) and it has the tag removal feature.  So I'm looking at my list of tags, and I see that for some reason, Dolphin allows duplicate and more-triacate (lol) tags.  Rather than going in here every other day or so and removing the duplicates, is there a better way of handling this?  Or, is there a way to actually avoid it all-together?