Tubes?

There are 2 options.
1. Use a tester, but some only give you a good-bad decision, no idea of how good. Its been a long time since they've been at the five and dime (a long time since there has even been a five and dime), but you may find one at your local independent hi-fi or tv repairman, or if you post your location, someone here may volunteer.
2. Sub them in to a component that uses the same tube type, but again, that will only give you a go-no go decision

I would either send them and pay a small fee to a reliable Tube supplier..or Ask someone on this Audiogon site that has knowledge and owns a calibrated tube tester to test them for you.....Other than that its not worth taking a chance unless your willng to take that risk?

It's also possible the tubes you've found are not worth the trouble even if they test perfect. Of the thousands built, only a double handful remain popular in high end audio.

If you list what you have, I and a dozen others here at Audiogon can tell you if they are desirable. If they are desirable it's worth testing them and putting up for sale or keep for yourself.