It can take time, but if you`re persistent they`ll get more and more tame every day. It`s a little easier now that they`ve been seperated.
If they haven`t had their wings clipped yet, that`ll make this a lot easier. Don`t attempt this by yourself, though, unless you`ve done it before. Have someone with experience teach you how.
Then I would recommend getting one of them out of the cage and into another room that it`s unfamiliar with. You can either quickly towel it and carry it out of the room or carry the cage into the other room, take off the top of the cage, and flip it outside so he`ll climb out (and then push the cage out of the room once you have the bird out.)
Once you have the bird out of the cage, offer it its favorite treats (millet spray, sunflower seed, etc) and favorite toys, play music, talk to it, sing, etc... Anything to make it get used to you and enjoy spending time with you. Eventually you will try to get it onto your hand, to teach it to step up from hand to hand, and to step down onto objects, and back up onto your hand.
You can also try gently wrapping the bird with a towel (covering the eyes to keep it calm). Expose only the back of the bird`s neck and gently rub the feathers there. If the bird relaxes and enjoys it you can try to move around to the chin and gently rub there, as well. If the bird doesn`t calm down reasonably fast then this is probably too stressful for this particular bird and don`t try to use this particular technique.
I also recommend taking plenty of time during the day to always stop by the cages and say `hi` briefly, whistle a few tunes, sing a few songs... and drop a small treat into a special treat-dish in the cage. They`ll start to associate your visit with good things.
Goodluck!