I hope it helps! Bad dreams are such a pain to deal with. For purifying the hagstones without salt or smoke, I'd just use some clean water and maybe a touch of something with purifying properties, myself. Maybe let soak with a reed in the water with it to absorb impurities, or rinse it with water + juniper berry juice are the first examples that come to mind, but variations on that theme with other ingredients if you can't get those easily can certainly be done. I'm happy to help brainstorm if you like!