I just soak mine in StarSan.
I fill anywhere from 3-5 vials from each batch for reuse later.
Do you just scoop right of the yeast cake or do you wash the yeast first? I was thinking about just scooping off the cake with a sanitized spoon or dunking the vial right in after sanitizing it.
I am guessing you just store in refridge. Do you add any boiled water? Or wort?