As I am quite an Twitter Addict, I tend to surf a lot on that Social Media Site, blowing my Android Cache to unfriendly-sizes. In earlier days, I installed some random Cache Cleaner from the PlayStore, cleaned the Caches and directly uninstalled those Apps again, as they tended to be full of Ads. However, in recent days, I saw that most Cache Cleaners did not work - even though "the devs said so". How come? Well, I found my answer on the Github Repo of the android-cache-cleaner: "Starting with Android 6.0, CLEAR_APP_CACHE permission seems to be no longer available to regular applications and since this permission is required for cleaning of internal cache, Cache Cleaner is not able to clean internal cache on Android 6.0 and newer. However, cleaning of external cache is still supported." Well, cool thing. So most of those apps are useless as hell. But how to clean all the caches?!

TL;DR:
You do not need [an] app anymore if you are on Android 6.0 or newer. Just go to Settings & Storage -> USB -> Internal storage and click on Cached data in order to clear all the cache.

Source: https://github.com/Frozen-Developers/android-cache-cleaner/blob/master/README.md