Hi Marlo, Either isopropyl alcohol (= isopropanol) or ethyl alcohol (= ethanol) can be used as a dehydrant/dessicant with equal success. I use ethanol (about 3-4 gallons a week) here in the tissue laboratory where I work, for dehydration of tissue samples prior to histological studies. Ethanol is the most commonly used dehydrant in this kind of work; however some laboratories do prefer isopropanol, and I myself have substituted isopropanol on occasion, when ethanol was out of stock. Ethanol has a greater affinity for water, and a somewhat smaller molecular size, so theoretically it may penetrate and dehydrate tissues somewhat faster than isopropanol, but the differences are not major. Otherwise, they should work equally well. Either can be purchased in a pharmacy as "rubbing alcohol". Read the label - some rubbing alcohols are made from ethanol, some from isopropanol. For dessicating samples, the concentration of alcohol is more important than the specific alcohol used. You mentioned using 70-75% alcohols. These do a pretty good job, but of course they will not completely dessicate a sample, since they contain 25-30% water (which subsequently evaporates when you dry the shells). However, dessication would be more thorough, and drying faster, if you used a stronger concentration of alcohol. 90% isopropyl alcohol is often available in the pharmacy. The hydrogen peroxide recommended by Jim and Bobbi should do a good job of deodorizing, but not in the same way as alcohols. Peroxide works more like bleach. They are both in a category of chemicals known as strong oxidants. They can destroy odoriferous compounds, and even dissolve soft tissues of a mollusk. But they do not dessicate, since they are aqueous solutions (almost 100% water). Alcohols on the other hand, dessicate tissues, but will not dissolve them no matter how strong the solution or how long the exposure. Paul M.