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An easier way to revive an NST?

Original poster: "Garry F. by way of Terry Fritz <twftesla-at-qwest-dot-net>" <garryfre-at-pacbell-dot-net>

I have gone thought several NST's that were shorted and I note one thing that
seems to be in common with all of them.
Cracks in the tar. This leads me to suspect that it isn't just the presence of
tar that is the culprit but cracks in the tar that allow a channel of air to
become ionized and conduct a spark that burns a carbon trail in the tar -
shorting the NST.
I also note that the unpotted NST I am using that is inside a mineral oil bath
had copious amounts of tar in between the windings. The mineral oil is quite
black and yet the NST works like a champ with no signs of trouble.
I have an idea I am going to try if I ever need another NST. I think that this
might be a very long time at the rate things are going with the NST lasting so
long and having a spare too so maybe someone out there can give this a try and
put an nst through a workover to see if this idea works revives and prevents
further breakdown. ....
The idea ... Melt most all the tar you can get out of the NST, leaving the NST
core inside the case. If successful, the carbon track will be melted away. Then
pour mineral oil inside the NST, replace the top and seal it up with silicone
seal and just try to get it to break down again.
What I suspect will be found is that the oil will soften the tar helping to
prevent further cracks and the oil will fill any cracks as they form and you
will not be able to cause another short in the NST.
You see, I have this unpotted one, and it apparrently had plenty of tar left in
between the layers of the secondary and yet, it never has shorted. 
Could someone try this on one of their dead NST's and let me know the results?
If this pans out, there will be no more need to depot and fuss with a lot of
messy tar and solvents, no more dinging of windings, no more NST's destroyed
because I soaked them so long in mineral oil that the paper layers in the
secondaries disintegrated. If this works as I expect, it will be the best thing
since sliced bread.