Scrapping transformers

I have some transformers that I've been scrapping. These are not the big ones on utility poles that have oil in them. The kind I get come out of battery backup units and phone systems. They have the laminated metal and have been dipped in what I believe is varnish. Is there anything in these transformers that I should be concerned about when I break them down?

If your grinding/cutting the end off, just don't breathe the dust.

No cutting or grinding necessary. After I remove the 4 bolts that hold the mounting brackets on I can take a hammer and knock the end off. I've noticed that most of the older transformers seem to have more varnish on them.