I did get out the scrubbing brushes and hand-cleaner and did 
a pretty-good degrease of the apron tin and air-cleaner stand for
my pickup, and the set of junk-yard heat-exchangers I bought. After
washing them I plugged one exhaust outlet with my hand and blew
into the other- they hold pressure, at least by that crude measure.

	Both of the 'new' exchangers have heater-flaps in good condition,
so the trick is now to figure out how to do a transplant, ideally
without disassembling the old exchangers which are already bolted to the
engine and the rest of the exhaust system. Now that I've got nice
clean, rusty, new ones, I can put 'em on the bench and figure out how
to pry the flap mechanism apart for transplant.

	Other alternative is to pry-out the old exchanger's flaps
and have someone fabricate replacement arms for 'em, using the
new one's a guides.  That might be a good idea, actually.

	The under-cylinder-tin came with the exchangers, and was so
gross and oily and beat-up I didn't even try to clean it up and 
dump it into metal recycling. It went to the landfill this morning,
and is Officially Not My Problem.

	I remain convinced that Gojo orange hand-cleaner, a stiff brush 
and running water are the superior de-greasing setup.

	Bill