So, after posting
the lamp was on my mind. So I sat down and soaked it with Goof Off (Piper, great minds think alike). Unfortunately it had no effect on the tar like stuff.
So I applied heat with a micro torch. I had to get it really hot and the tar started melting. I was able to unscrew and separate the parts
(with hot pads for my hands). It was very hot.
I tried to wipe the parts but it won't come off, even when hot.
It appears to be very old oil or something. It's all over and the wick is hard and stiff with it.
I have it all apart now and I am thinking of trying carburetor cleaner or thinner next. Otherwise I will hit it with the dremel and wire wheel
. That is last resort because I don't want to mar the patina of the brass.