Caleb at CSI says in his potcast that he has never gotten a male from any of the thousands of his own fem seeds he has grown.
Zero.
He believes the phenomenon of males in fem seeds is stray pollen.
I don't care what he says on his pod cast. It happens and several people have documented it here.
I've seen it happen personally and I know for a fact it wasn't stray male pollen.
I plan on making some colloidal silver and try reversing a female for some chucking. Seems like a straight forward process. Spray plant, collect pollen, use pollen, grow seeds, check offspring if cool then continue to use pollen.
It is straight forward. A bit of advice. I make my fem seeds.
Start spraying a couple days before you flip to flower. Spray daily into the flip until the stretch starts.
If you wait until bud formation it doesn't work as well.
I've done branches and whole plants. Whole plants work better than branches.
Other than that it's straight forward.
Lysol spray kills 99.999% of germs.
I thouroughly clean my grow area between grows with bleach water.
I also use hepa filters for the intake that filter pollen as well.
I wash up and wear clean clothes when I mess with my grow. That keeps pollen as well as mites out. Since I grow vegetables and other stuff outdoor I don't want pest coming in with me.