Powdery mildew is HERPES for plants. It will not go away. You may get it to hide for a while, but it is there.

So, if you are going to clone those plants or ever bring other plants into that grow area they will all be affected as well. I shut down for 6 months to make sure I got rid of PM after dealing with it for many months. All fans and walls and such should be disinfected as well.

And making the analogy to the wine industry is silly. The grapes are not getting infected, the plant material is. Fruit is still fine. With Herb, the infected part is the good part and it is just not worth it! I get PM outdoors on my Lilacs, cukes, and squash and they are all fine. Again, because the fruit is fine, the plant material is suffering.

I would get some seeds or some clones from a more trusted source.

Good luck
sittingone