Both of these are/were chemical solutions for creating a black finish on a variety of metals, most commonly Brass.
Apparently Blacken-It has a finite shelf-life: A not-that-old bottle of it is about as powerful as pure water at changing the color of a piece of cleaned brass but the last few drops of the 30+ year-old bottle of Hobby Black are still quite active and produce exactly the desired effect.
SO ...
I've found several sources for Blacken-It but a Google search turned up only a few older references to Hobby Black. Is it really no longer made? [I'm sure we'd have the CPSC and the EPA to thank for that]?
Are there any substitutes for Hobby Black that are more effective and longer lasting than Blacken-It?
TIA Norm