I guess you mean the neutral extractors found at uncolonisable wells such as gas giants, nebulae, etc.

the TEC and advent use their colony frigate, the vasari their scout. these ships each have the ability to capture neutral resource asteroids. it does cost anitmatter and has a long cooldown though. also beware that these 'roids cannot be destroyed, ever, only capture from other players.

be sure to get as many of them as you can (and defend them), they are a great boost to resource income early on.

One thing Shadowhal didn't mention is that the Vasari scout won't capture the neutral extractors if you've set explore to autocast (or at least mine don't).  Once you've got a scout in there cancel any existing move orders and disable explore... it'll quietly get on with capturing.

Then you can send it merrily on its way again when it's done... as it can't really defend them... it's a scout.