[I am NOT an expert but have done a bit of reading in this area.]

>about pcb's : I was told when I got an old xformer that had been
>constructed in the 50's and has some pcb-oil as insulation that
>pcb's aren't really that dangerous unless you drink the oil :)
	So said the salesman.

>or _burn_ it
	PCBs are used because they DON'T burn.  If something else in a PCB
	cooled/insulated transformer burns, OR if the PCB's overheat to the
	point that teh case ruptures (or the vetn fails or....  The PCBs
	get somewhat vaporized & somewhat aerosolled & can get ingested/inhaled.

> - that's how the nasties are formed according to him..
	My reading indicates something more subtle:
	PCB means Poly Chlorinated BiPhenyl.  Which means a biphenyl with
	somewhere between 2 and "poly" Cl attached.  The usual soup is a mix,
	because, for electrical purposes (insulation/cooling) the purity in
	this regard is not that important.  SOME of the highly Chlorinated
	biphenyls are nasty.  Most of lower ones are not.  Or so i recall.
	Also, there are some random trace "whoknowswhat" from the production
	process that don't hurt the operational characteristics, so they get
	left in...

	For myself, i would not use them.  If the seal is good...  Also
	_modern_ "transformer oils" have a different chemistry.