The Galvanic Spa Pre-Treat and Treatment Gels were specifically packaged to provide the optimal amount for one galvanic session. We do not recommend saving any unused portions of gels for use at a later time. Storing open vials of gels allows the possibility for serious problems regarding product safety and efficiency. Additionally, the active ingredient in the gels can become neutralised or oxidised in an open vial, rendering the gels less effective for their intended galvanic applications.