I had a vasectomy 6 years ago. Can I still have my semen extracted and frozen?

I have had a varicocele for more than 9 years, although I have been able to have children since having the a varicocele. The problem causes a serious inconvenience with constant aching on the left side and sensitivity throughout the day. I have read that Hammelis Virginiana is potential treatment for this disease, can you provide some information on this and also what other treatments that are recommendable?

I'm 28 year's old, 5'7" height and 67 kgs weight. I want to sell some of my sperm. How do I go about doing that? Is there a process?