As a Pharmacist, any pharmacy will have glycerin...it is used as a softening and suspending agent. If you can't find it in the regular aisle you can always ask if they can order it for you.
Distilled water is really the only thing you should use for any mixtures because it doesn't have any chemicals. It's really cheap and lasts forever!
You can use it in your iron also since it won't cause any of the yukky white spots when you steam things.
These are great recipes...thanks for posting them.