[morzh]

At least something was easy; the fortune smiled at me tonight: the backelites were a snap to re-stuff. They barely needed heating and the contents snapped out readily with minimum of chipping of the tar and such.

Also I discovered an easier way of pushing out the potted contents out of the backelite shell: I leave the cap in place without unscrewing it first. (of course I bite off the wires). Then, provided I have the space around it, I heat it with a milwaukee gun on one side, and I keep the gun on Low for 10 sec, giving it a 2-3 sec Hi blast, and then repeat it with the opposite side. I think keeping it Low would also work. Hi is useful if there are no sensitive parts close to the cap that could burn/melt.

Then without unscrewing the cap I push the Allen wrench of the thickest possible gauge that fits through the central rivet inside and push out the contents.
Then I unscrew the cap, turn it and pull the contents out.

Why?

Well, for starters, when you heat the cap, you have to hold it with your fingers and that may be somewhat uncomfortable as it may be fairly hot.
Second you have to hold it tight with your fingers and provide the resistance to the push of the allen wrench with your hand and it is usually somewhat slippery due to the old grime and skin oils and all other stuff.
If however it is still screwed in place you do not need to hold it, burn your fingers and flex your muscles - you simply push the wrench (or what have you) 'till it snaps out.

One thing though - it works because the caps I have have the bushing through which the screw goes raised relative to the potted surface, so the potted block has the space to come out. If for whatever reason there are such caps without this feature and the potted surface is flat against the chassis, it won't work. I am not sure if such caps exist or it is a product of my false memories.....