Reading this is exactly why I never buy street weed and grow my own.
Treat the cause and throw away all the plants start again from scratch! Or you could sell the buds to somebody that you hate?
If I ever get powdery mildew I will just accept it was an environment mistake and fix it, but start over...!
Mildew buds... I feel sorry for the unsuspecting poor bastards that are going to blindly smoke this.