[Heathkit] What is this black stuff?

[Ron Youvan]

> Some (not all) of the joints with an overly generous amount of solder are a 
> bit scary.
> When heated a black goo boils out of them. This stuff immediatly fouls my 
> iron's tip.  But it cleans right off of the iron.

> I've carefully inspected the pad and wires where this stuff was and am not 
> finding any corrosion... I thought it might be acid core flux that I'm seeing, 
> but I just don't know..

> Any idea what I'm looking at? Cause for concern, or just some strange solder??

   What does the "smoke" smell like?  Vaguely like pine?
I will guess it's very old oxidized rosin from the original soldering job.
-- 
    Ron  KA4INM - Please pay your taxes promptly
                  our illegal aliens need the benefits!