Android 4.2 Jelly Bean lets you clear all cached app data (temporary files accumulated by apps) with a tap. All you need to go to settings – storage, and tap on the new “Cached data” section in the list. You’ll be prompted to clear the cached data.

Keep in mind that, deleting cached app data will cause some issues with some apps, for instance, you may want to re-logins to apps, requires long time to load app, etc. However, it can help improve performance of your device. [via]