So how do you tell a dancer to move on?

OK, so I'm pretty much a PL asking for some input.

I've been going to SC for a while now, and it may be that I've mellowed with age.  Or dancers are getting more aggressive.  I think I'm just too polite for my own good, but whatever.

Dancers seem like they can sense this somehow, at least some can.  I don't care much for the "big" crowded clubs with valets and outrageous drink prices and such, I like a club where I can go in and not feel like I'm in a rock video.

Unfortunately, in clubs like that, I usually end up with one of two situations: (1) a dancer will come up to my table (or next to me at the bar) uninvited and without any preamble just sit down and start talking to me forever, or (2) I'll get a dance, or even just tip her onstage, and the girl won't leave me alone the rest of the night.  I've had ATF's in the past and that can be great (for my ego if not for my wallet), but ... sometimes it's not-so-great.

So my question, I guess, is this: what's a polite way to tell a dancer that I don't want any (or any more) dances from her, I'd like to spend some time with a different dancer (or alone just watching the stage) for a while?  I don't want to offend her (since I know how dancers talk) and I certainly don't want to tell her that she's too ugly/fat/boring/old for my tastes (since mostly that's not the case).  Is there a nice way to say "Hey, I've enjoyed talking to you, but please go away now?"  Note that sometimes there is another girl I'd rather spend a little time with, and sometimes I'm just interested in looking, and I may (or may not) be open to having the dancer in question come back later on.