Why no water for vulcanite? I always rinse the mouth bit (outside) after smoking and dry with paper towel. I have also been washing them when deep cleaning with neutral soap and water.
You ca use water on vulcanite. If you are rinsing them and washing them, you can wipe the polish off the stem and make it oxidize faster. Just wipe it off ands put whatever oil you use (Obsidian, mineral, olive, etc) it afterwards.