I'm late to this party... but I've used M&M Tonic FO... I don't recommend it - or at minimum if you plan to sell do a test batch and keep for at least 6 months before you make a batch to sell. I made soap with this FO twice, two different recipes, and both had DOS within a few months. Both of my recipes are good and I have soap bars that are 5+ years old, so it's not a recipe issue. I used it in some b&b products, and the fragrance went rancid. I have had issues with almost all of the FO's that I buy from M&M, so I only buy colors there now. Shame, because it is a lovely fragrance.