Teardown?

[nachoman]

In my opinion, ballast is relatively cheap and not worth the trouble to try and save. If you are really tight on budget, find a place nearby where you can "quarry" your own. Screen it to the right size, bake it to kill all the critters, run a magnet through it, and use it like you would ballast you bought at the store.

If you really want to save it and it is glued with white glue, it can be soaked in detergent and warm water, rinsed several times, and dried. If you used matte medium, it is insoluble with water once dried.