I say hang on to it.
When and if she asks for it back, hand her a bill for services rendered to date as well as storage charges.
Explain to her that "She no pay she no get"(that is sarcasm there). But the truth none the less.
Most if not all places where you leave something, has the policy that if it stays for more than 60 days without payment or having made other arrangements it becomes the property of the person doing the work.
If she was a "friend" she would understand that you were giving her a deal in the first place. Come on now. If a mechanic has to fix what you screwed up, he's gonna charge extra to take it back apart to repair it properly.
Sorry but she sounds pretty selfish to me.
I do not see that you have done anything wrong, nor should you have to give it back if you have already started working on it.
I'm thinking that she may be embarressed to come back. Seeing as how she made a fool of herself for saying that to you. She should be ashamed of herself.
You should have asked her if she kisses her Mama with that mouth... LOL!!!
And that Ladies is only my opinion...:-D
:XD: