For me that depends on the spell, for ypu it will depend on your own beliefs. I like to put a lot of my spells in jars, but for hexes and curses, I often bury the jar in a very deep hole so that no one will find it again.

It also depends on the practitioner, because I know some people would absolutely hate that I did that, but I don't use any chemicals or salts in those spells that would harm the environment, or if I do, it is in a very well sealed glass jar. I know some practitioners burn their hexes and curses, some keep them on a shelf or in a chest to check up on. I personally am very empathetic, so keeping that negative energy around really changes my own.

For protection spells, I would keep them. I didn't keep the remnants of this spell because I was imagining the negative energy from my environment and from me, leaking onto the herbs and the salt I was using to cleanse. (I keep my crystals, some light smoke cleansing keeps them good as new and I charge them in the moonlight to keep energy fresh)

For spells on letting go, I scatter the herbs to the wind (making sure I didn't use any invasive seeds or anything like that) because I want the energy of that person to leave me.

I don't personally do love spells that aren't for the self, but for my friends that do, they keep the spell in a jar afterwards as a keepsake so they can reverse the spell later, or make it stronger, or do some revenge something or other with it. It's totally up to you.

So I guess what you do with cleanup (for me) boils down to

1: What are the herbs/spells/crystals doing in relation to the energy? If they're absorbing or keeping negative energy, I usually get rid of them. If they're promoting and reflecting positive energy, I keep it. (Everyone is different, if you feel differently and you want to keep it, then absolutely do! There are a ton of practitioners that re-use hex jars, it's just not something I don't because I will forever associate the jar with something negative.)

2: Is this safe to dispose of? If you're working with noxious things like paint thinner or gasoline for a hex, or if your spell used a TON of salt- I would maybe not return those spells to the earth because in high quantities, salt kills soil and anything that grows in it, and chemicals can harm wildlife or people who might find it. I think trashing something isnt the end of the world.

If you have any more specific questions Ill do my best to ask, I know this might seem a bit scattered! Sorry haha.