Ok so here is an idea:
You need to have a place where open fire is ok.
Get two iron containers. Place one over the fire and throw all of your motors/transformers into it. Let it roast for like 20.
Have the second one filled with ice water. (I'm a chef so I have plenty of connections on free ice in the business).
Use hefty fireplace tongs to get the motors out from one and into the other.
The process of rapidly heating and cooling materials makes the steel very brittle and much easier to rip the Cu windings out.