Back when I wrote some basic guidance on how to do no-frills worship (and a follow-up one on doing quick worship), I said that one could easily buy rosemary to make purification water.
I had occasion to buy a lot of fresh rosemary, and these are 6-8″ sticks.

I’ve lain them out on a flat surface to dry (which rosemary does beautifully, rarely going moldy, due to its hardiness). The flowers on the rosemary make me wish that I had had this before the beginning of the Anthesteria, as I could have used those sprigs to decorate Dionysos’ shrine.
Once they’re dry, I have a small Mason jar that I use for purification water. I buy the least expensive sea salt I can find and add one tablespoon of salt to water. As I have previously said on this blog, I set the rosemary on fire using my just-lit candle for Hestia, usually with the Mason jar of water in my hand beside the candle so I can cut down on fire risk. I extinguish it in the water and sprinkle myself with the saltwater.
If you buy rosemary from a grocery store, it will often come in plastic boxes. I recommend removing the rosemary to dry immediately because the sprigs are often folded, which makes the stems more fragile the longer they’re warped like that. It’s important for fire safety reasons to make sure the sprig won’t fall apart.
Also, as a final note, the Eumenideia is coming up in a few days. It’s a great time to do some extra purification.
💧