I scrap heaps & heaps of them.

Look at it, see the bit in the centre of the copper coil?
Now if you put the thing sideways on a solid surface & tap the end with the big hole in it, just a few taps with a hammer will do.
That will open up the end where the copper coils is.
Now the copper coil & the inner part made of iron will drop out.
Now use something to push the inner bit of metal out & you are left with a complete copper coil around a square plastic spool.

Cut thru the spool in the middle with a meat cleaver sorta tool & hammer.
(I wouldn't suggest using a craft knife/boxcutter, as they have the effect of not cutting thru, until your finger is under the blade, then it slices thru the plastic & your finger....)

Peel off the copper coil, I did aboput 5 last night.
They weigh up to about ~ 50grams