If you don't mind having your own device shame you into better habits, Droid Optimizer is the best Android cleaner for you. It offers a 'ranking system' designed to motivate you to keep your device in tip-top shape. It's simple to use, especially for newbies, with an introduction screen that walks you through permissions and features. Droid Optimizer is one of the best-known Android cleaner tools, with over a million downloads on the Google Play Store.