OK, it's not used up or dead, it's just not the best, freshest, or most active to use.
With the Polyclar already in there you would be trying to ferment and clear at the same time.
conpewter: as for "Palmer says he uses yeast from the secondary when he's washing yeast. He says that in theory over time you'd be propagating the less flocculate yeast but I see no issue re-using it one time."
Why would you want LESS flocculate yeast? If you are brewing a weizen you would want the yeast to stay in suspension.
Maybe he doesn't do secondaries or filter either, but that doesn't make either practice wrong.
I'll stick to washing yeast from the primary.