Welcome @michael10! 
You’ve got some great advice here, just wanted to share a link to a post that was really helpful for me: Disposal of Spell Remains. You might get some additional ideas there too!
While it is largely up to the individual, I personally don’t see any issue with reusing spell jars that were used in positive spellwork, especially if the next spell you want to use them for is similar to the first 
Good luck! And please make yourself at home here in the forums. Looking forward to talking with you more soon- Blessed be! 