transformer depotting/postmortem

["Stephen Carpenter" <sjc-at-xxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

As both of the transformers that I had died, and thus I can no longer run
my old small coil (need to get new transformers and start on a new coil...)
I decided to follow the advice I saw here in another thread and try to
depot my transformers and do a post-mortem. Who knows - maybe I can get them
working or even junk the windings and re-use the cores?

Anyway...I have come to a question. I gave up on "Saving the case" when I
realised that it just wasn't that important. So I chiseled it off and had
a good time about it. Unfortunaly, probably due to lack of skill
at cracking ceramics with a chisel, I broke my lead wires :( (well most
wires :(

I only have access to 1 of the primary lead wires (the secondaries aren't too
bad). 

I have decided to "freeze and crack" the casing off. The methods I have seen
here and on the web are to freeze it good and solid, then power the 
transformer and short the secondaries to "cook" the inside for 15 mins, then
to crack the black gunk off with a chisel.

Does it NEED to "cook" first? Will I be completely unsucessfull if I skip this
step (rather than digging and fishing out the lead wires from the asfalt)?

-Steve
-- 
A scientific truth does not triumph by convincing its opponents and
making them see the light, but rather because its opponents eventually
die and a new generation grows up that is familiar with it.
                -- Max Planck