If you want to sell them "fast" then Afternic is out. You will need to go with an auction format which Afternic doesn't offer.
You have to apply to sell your names in NameJet auctions. I've never done it, but I think there will be some time delay even if you are accepted.
So, Sedo is probably the fastest of those 3 to get rid of them. Anyone can do auctions at Sedo I think, although I've never auctioned my names there, either.