Tax-free alcohol withdrawn by clinics operated for charity and not for profit shall be used only for medicinal, scientific, and mechanical purposes and in the treatment of patients. Medicine compounded with tax-free alcohol may be dispensed to patients for use off the premises, if the furnishing of the medicine is not conditioned upon payment. A separate charge may be made for medicine coumpounded on the clinic premises with tax-free alcohol for use of patients on the premises. Except as provided in this section and in § 22.102, the use of tax-free alcohol shall be confined strictly to the premises of the clinic.