wow, that's scary. I inherited Georgie (7yr old male) a year ago. He was REAL bity. I had lots of scars because i'm a petting kind of person, but i learned about him & he learned about me, so now no biting & he knows that all i want is to kiss his beak and tummy, not hurt him.
Funny thing about nail care. I happened by luck, I trained him to shake my finger (hand), you know, by rewarding with seeds, and once i decided to file his needle sharp claws while putting him on his back (he likes a nightly head massage, he's SPOILED) . He SCREAMED!! wouldn't let me do that. Time passed, & than while he was shaking my hand on the training perch, i made the nail file a new game. I picked it up , touch his foot with it & IMMEDIATELY shouted cheers, clapped, the whole "good boy" routine with LOTS of seeds. After that, he didn't mind it. Now he acts as though it's about time Mom got around to my manacure!
I have the best luck with new things, when I cheer insanely & feed him if he does something I want him to do. So far so good:)