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.

This is because most of their "cleaning" techniques come from the world of PCs, and do not apply to Android. Instead of speeding up a phone, these system optimizer apps are more likely to just bring ads to your device.

Some are even suspected to spy on the user, and to pass on information on their behaviour and device.

You're better off using Android's built-in tools, instead of installing pointless or dangerous apps.

Two tools can easily be found in the settings:

– The cache: Normally apps themselves make sure that not too many files end up in the so-called cache of an application, a reserved space for temporary files. These are usually deleted by the app itself.

However, if an app suddenly starts to run slowly or with errors, it is possible that something is wrong with its cache. In this case, it is worth trying to empty it manually, under Settings. Once you've found the app in the Apps section, go to memory and then empty cache.

– The RAM: It is a common misunderstanding that the working memory (RAM) should be as empty as possible and that the background processes of apps should be terminated as soon as possible. In fact, it's the other way around: Android is designed to use RAM as much as possible.

If you start a new application and there is not enough RAM available, the Android system automatically takes care of it: It closes the longest-running, least important applications one after the other and leaves important "long-running" apps like messengers untouched.

The only exception to this rule is that you do sometimes need to kill an app when it crashes or hangs. In this case, it makes sense to manually terminate the app's background processes by finding it in the "Apps" section of the settings and then tapping "force stop". – dpa