A friend of mine asked how I make my bath salts, because lately I'm on this kick about how many things we buy from the store when it can be made at home with fewer artificial ingredients and many times it will cost less.
Bath salts are incredibly easy to make, and so long as you have a good sealable container can last several months. Be aware that any essential oils that you use in the mix will change the shelf life of the salts. (If your lavender oil has been sitting in your cabinet for a few years, you should probably get new oil instead of using it. Herbs, even in oils, lose their vitality over time.)
Bath Salt recipe:
6 parts coarse salt - usually kosher or sea salt
3 parts epsom salts - these are in the drug store, and are actually magnesium salts. They help to relax the body.
1 heaping tablespoon of baking soda - this softens the water in the bath.
1 tablespoon of olive oil - great moisturizer for the skin, but be forewarned, the tub will be slick after your bath from this key ingredient.
If you are using essential oils, a little goes a long way. I usually do the drops in five drop increments. Five drops for oils that are likely to be overpowering, such as any of the mints. Ten drops for those that are somewhat less so, such as lavender. Only rarely would I ever go above that amount.
Mix all your ingredients in a bowl, preferably ceramic. Some herbs can be altered by contact with aluminum, so if you are using essential oils, keep this in mind - no metal bowls or utensils! Also, avoid using a wooden bowl for this sort of work. The wood absorbs the oils and can eventually contaminate anything else you do in that bowl.
Ceramic is where it's at, folks. Or other non-porous non-metallic substances.
Mix the ingredients thoroughly. If you want, you can add food coloring, but I don't. When trying to make something that's free of nasty additives like what's on the store shelves, adding food coloring can introduce all sorts of fun and unpronounceable substances!
Honestly, I think the stuff is divine without the addition of essential oils. Always consult a reliable herbal before playing with any sort of herbs. Herbs can interact with your medications, and can trigger your allergies if you aren't careful.
I don't make any of my herbals often anymore, because in an apartment, there just isn't room for some of the things I would really need to do it right, but this is one recipe that I continue to do from time to time.
Of course, don't ingest this stuff. Epsom salts are not your friend when taken internally.
That said, I'm not a doctor or a professional herbalist. :p
I can say, however, that my personal experience is that my skin is extremely soft after using my bath salts, and that with some candles and incense, they can make for a very relaxing few hours.