Cleaner apps: Useless, risky and a waste of your time

Lots of apps tend to slow down your phone. But installing yet another one claiming to be a 'cleaner' that speeds up your phone will only make things worse. — Arne Immanuel Baensch/dpa

Cleaner apps promise to free up space and speed up your Android smartphone – except most of them are a waste of time.

It might be satisfying to tap a button that says "optimize", but consumer watchdogs say there's no need to install any of the many apps on the Google Play Store claiming to clean up or optimize your phone's operating system.