Useful Cleaner is a free Android app developed by Q-Up Corp. that helps users optimize their devices by cleaning out junk, residual and cache files, and hibernating unused apps. It also provides a power mode changing feature that can be useful in prolonging battery life.

The app is easy to use and provides a simple and intuitive interface for users to navigate. Upon opening the app, users are presented with four main features: Junk Cleaner, Residual Cleaner, Cache Cleaner, and App Manager. The Junk Cleaner scans and removes unnecessary files that take up space on the device, while the Residual Cleaner removes files left behind after uninstalling an app. The Cache Cleaner clears cache files that can slow down the device, and the App Manager allows users to hibernate or uninstall unused apps.

It is important to note that some features of the app may not work or may work incorrectly on certain versions of Android due to the operating system's peculiarities. Overall, Useful Cleaner is a useful app for keeping your device optimized and running smoothly.