Old scratch cards from previous years still work, and can be reused up to five times, but only for the same candidate’s examination number each time. Old scratch cards from previous years still work, and can be reused up to five times, but only for the same candidate’s examination number each time. WAEC now lets you recover your Serial Number and PIN electronically, using the National Identification Number you submitted at registration. How to Check Your Result Through the WAEC Mobile AppIf you’d rather use your phone than a browser, the WAEC Result Checker app does the same job. Search for “WAEC Result Checker” on the Google Play Store and download the app carrying the official WAEC logo.