If its those exact transformers, I would break them down in a heartbeat.
If you have a anglegrinder, just grind a light gouge down thru the weld and hammer that part out.
Then put the rest of it into a loose vise, or between two blocks or something, and use a hammer and punch to push the 'E' out of the two coils.
Then clean the cardboard insulation off the coils to get 'Copper #2' price for it.
Pick as much insulation off it as you can, down to the point that if somebody was watching you do it, that the size of the bits you were picking off were so small that you would feel a bit silly in picking them off in front of somebody...
That's how I do it, if somebody complains, let them pick some of it off in front of you, they will feel silly about doing it pretty quickly, and the amount they pick off will be negligible anyway by then.
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