How to Clear App Cache on HTC One
Android applications save cache and data on your Android phone's memory. You can easily clear app cache, clear app data, and force stop apps on HTC ...Continue
Samsung decided to change the functionality of Galaxy S5's 3 touch buttons and Menu Key is no longer one of the options, as "Showing Recent Apps" replaced with the Menu key.
But it doesn't mean, you can not use the touch buttons as menu key on Galaxy S5.
To bring back the Menu Key on Galaxy S5, you just need to hold the "Show Recent / Open Apps" key which is located left to the Home Button, as it functions like the Menu Key you've already seen on other Galaxy devices.