Course you can! All you have to do is check to see if it sealed. If you're concerned about a jar, keep it in sight and check on it every few days. One thing I like to remind folks about to help them feel more confident about preserving food is this: The FDA didn't exist 100 years ago. Those folks recommend and warn about all kinds of nonsense that many generations of folks before them did their whole lives and survived just fine. That said, everyone's got to weigh these things out for themselves and do what feels right to you.
But, I still know folks who can, and even vacuum seal, re-using jars from the grocery store! Pasta jars, jelly jars, etc.,
Here's the best advice I was given regarding
food preservation and learning what works and what doesn't: Whatever method it is you're wondering about, try it out on a jar or two and keep an eye on them. If they don't seal or you have doubts about them, you can just pop them in the Fridgidaire and use them first or reseal them again another way that works.
Thank you in advance to everyone for their replies, help, and suggestions! Forgive me if I miss any replies, I'm still learning how to keep up with threads I participate in!