I used clicker training with my Grey when we "re-potty trained" her. Her previous owners taught her to jump on the floor when it's poopy time and poop on the floor!
Whenever she pooped in her cage, I'd click, give her a treat, and praise her. She eventually started catching on, so when she'd be outside of the cage playing, and you could tell from her body language that it's time to go, I'd put her back in the cage and do the same. Now I just say "Go Potty" and she gets it. It didn't take too long, a couple weeks before she quit realizing that the floor is a bathroom.
