Look at it this way. The films came free, cost you nothing, and if you put them in the trash tonight they'd not cost you any more than nothing.
On the other hand, you can mess around "testing", paying for processing, probably getting a lot of poor results and that's all going to cost you both time and money.
You're talking about film that has not been refrigerated and some of which is 10-20 years old.
Don't be cheap. Throw them all out without a thought and use fresh film - that is, if your images are important to you. If they're not, then no advice here is going to help you.