Unless you have a specific problem the could be related to cache files, they should not be cleared. Caches are there to speed up operation and best performance is usually achieved by just leaving them alone to do their job. Clearing caches also wastes power and CPU cycles since the caches will rebuilds themselves anyway. I never give cache files a thought.
But if you really feel you need to, Javier P gave a good explanation. No app required.
Android since v1.0. Linux user since 2001.