Sanctuary got attacked by raiders. When it was finished Trashcan Carla was in my best power armor. I always leave my PA without a core in them, but she still got in it. So I can't pickpocket the core, because there is none in it! Guess it's a bug or did something change and can some people use the power armor without core? Luckily I had a recent savefile, but how to solve it when it happens again. Talking to her does not work, no option to make her leave it like with settlers and followers.
How to get the trash out of the can, you mean? There's at least one option: Bunker Hill.
Random caravans will stop there from time to time - Trashcan Carla's included.
She's an educated person and will leave her armor before talking to her clients.
It's not exactly easy to find her there, though - I had to pay several visits (waiting didn't work for me).
Well you can always kill her and loot the armor off of her, since it's not that hard to find another frame. The alternative is fast traveling away and then fast traveling back I've heard that works.You could also try to put a fusion core in then go into Vats and shoot it I've heard rumours the suit can sustain the explosion. I was also thinking maybe you could trade with them take the power armor leave the frame. Since there's so many Power Armor Frames everyhwere.