I used to get Kodafix bottles that were left behind by students in a community darkroom.
I ended up with some that sat for maybe 5-6 years and had some "flakey" material that I surmise was sulphur.
Long story short, I filtered the gunk out and used it. I always did clip tests for clearing time to calm my paranoid nerves.
Bottom line, I wouldn't use it on any really serious/critical work.
I wouldn't trust the archival property.