These pre-saturated use once and dispose swipe-through head cleaning cards are designed to safely and effectively remove all dirt, magnetic oxides, oils, lotions and other contaminants from all types of concealed magnetic, photo and optic sensors on all kinds of reader mechanisms. Use on card reading scanners attached to cash registers, credit/debit verification machines and ATM/POS terminals to name a few. Use at least once per week for internal, low usage card readers and once per day for external or high usage card readers.