We don't suggest frequent use of a UV sterilizer to clean your Venus Cup or any menstrual cup for that matter.  UV rays can accelerate the aging of silicone.  It can fade in color, become less flexible, crack, or take on a yellow hue.   One cleaning, stain and odor removal tip that we offer is to set the Venus Cup on a sunny window sill for a few hours. Since there is no harmful byproduct that is produced when silicone comes into contact with UV rays, doing this once every six months to freshen up your cup should be fine but we don't suggest using this method monthly.