http://www.thesage.com/recipes/recipes.php3?.State=Display&id=102 In making the soap, you won't need a preservative, but you may in the final scrub. Have you looked at Optiphen Plus? It's paraben free, formalhyde free, and keeps out yeast, bacteria, and fungus. I would never recommend selling a scrub without preservative, as water will be introduced to the scrub, and you will grow germies without one.