I have some recipe ideas for cosmetic gels swimming around in my head. I want to make them using strong herbal tea, but years ago when I tried this with my creams they molded too quickly. I thought that making an herby tea to use as the water component would be awesome so I made a nice blend of herbs and used distilled (not tap) water for the tea. The cream was great but didn't last long. So now I use hydrosols if I want more than just plain distilled water. However the gels I have in mind would be made from specific wild-harvested herbs (like sweet fern, for example). I'm not sure that grapefruit seed extract alone is a strong enough preservative to prevent mold in this case, and I'm reluctant to use anything much stronger, unless someone knows of a safe, natural, unlikely-to-cause-skin-irritations/allergic reactions preservative. The sweet fern idea is because it's practically a miracle cure for poison ivy and I'd like to offer the gel as a product for sale. So it has to have a decent shelf life and not need refrigeration. Any suggestions?