One should not use components which are not clearly identifiable, or are of an unknown composition or provenance.... According to the NRA teachers course, anyway.
With that said....
Black oxidization tarnish is purely cosmetic.
Blue oxidization is leaching metals, and is structurally unsound. If you tumble it, and the blue spots turn coppery looking- those cases are done.
Cartridge metallurgy has changed considerably over the decades, but if the necks size and unsize without breaking, they should be serviceable for at least one use.
Now, if this is some old handloaders scrap stash, only god knows what is contained in the "number of times fired" category, and i'd be very skeptical. This is likely whats in the coffee cans, and Id probably scrap it. Without direct observation, we're doing "Dentistry over the telephone" here, however.
If these are once fired pieces of brass, Particularly in old boxes, I'd load up and fire away. Its "new to you" components, so you'll be doing load workup from square one anyway, riiiiiight ?
When did we stop using corrosive ammo and primers in commercial ammo and ammo components for reloading?
In some brands ( primarily eastern bloc, but there are exceptions) corrosive primers are still used. Corrosive berdan primers have a much longer usable shelf life than noncorrosive boxer, and as such are often the forefront of milsurp combloc ammo dumps and repackages *cough* herters.. ZQ *cough*
Unless you have some neat vintage components, you are unlikely to find any corrosive reloading primers, unless you are buying com-bloc military surplus berdan primers.
