Most are copper windings, the few I have found aluminium windings in were the real cheap sort made in the last 3 years & 'combination ovens' where they were a microwave
& grill/oven at the same time.
To get the winding off, put it in a vise, loosely, with the W shape pointed upwards & the copper windings sitting on the vise jaws.
Then, with ear muffs & glasses use a hammer & a steel punch (you can use a electric motor shaft) punch the middle of the E with the punch & drive the laminations down & out.
Most of the time you try & get most of them down before just punching a peice the width of the punch, after that the rest of the E's fall out.
Theres 2 little metal laminations & a red fiber covered copper wire loop too.
Don't try & burn that off, it won't burn.
Now you have the 2 copper coils, use a pair of pliers & peel off one connector tab & pull the wire out, unwind that & it will cut thru the insulation & tear the varnish covered cardboard off.
Snip the clip off & break & rip the rest of the insulation off, use glasses here as the stuff will get in your eyes all the time.
Don't break the coil apart, just get rid of the loose stuff & chip the varnish off.