When I first got my '85 Westy (the DPO said he never used the kitchen
equipment), the drain at the bottom, with the little cap and chain, was
plugged solid with rust.  I used a length of coat hanger to plunge it
out and vacuumed it.  I also removed the flue cover pieces and used a
shop vac on each port.  I heard all kinds of noise as particles were
being vacuumed out.

After that, I tried the fridge on propane and it lit right up with no
problems.  Yep, I'm going to pull the fridge one of these days and clean
it up right but, for now, it works really well.

Mike