How to get Trashcan Carla out of my power armor?

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).

You could just kill her and take it from her corpse. Not really any reason to keep her alive shes an unimportant npc.

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.