[sdiy] What to do with REALLY obsolete parts?

[dj hohum]

I've spent some of this morning sorting parts with an eye to thinning
out my working parts draws. I have several bags of what I suspect are
truly obsolete parts that have little to no value in any sense of the
word.

Should these just be thrown in the trash? Or, are there vintage synths
that make use of some/any of these parts such that it's better to use
the vintage part than replace with a newer part.

LM-710 comparators (in the TO5 metal can)
741 op amps (in the 14 pin ceramic package)
747  dual op amps
MC1558 dual 741 op amps

and the prize, the data sheet states that the following part was made
obsolete by the 741...oh my

CA3030 op amp (in the 14 pin package, with rust forming on some pins)