My parents used to make it for me in the mid 1980's. I think they just figured out the proportions for about 5% and boiled it up themselves (my CF doc told them to do this since it was before it was available commercially). They then kept it in a jar in the fridge for a few days, then made a new batch. Seemed to help a lot, as much a mycomyst back then, and I dont remember an increased rate of exacerbation from making it ourselves.