How to delete App Documents and Data for iOS apps like Twitter? Some apps like Whatsapp, Twitter and Instagram end up storing a lot of Documents and Data, way more than their actual size. 

I want the exact opposite of this: How can I delete an iOS app and preserve its data?

Is there a way to remove just the Documents and Data and leave the app installed?
Actually, most of that data is cached from the internet for the specific apps you mention. Twitter and Instagram cache images, tweets, posts, etc. from the Internet. There is currently no easy way to remove them, however, you can send feedback to Apple here, and tell them you want a way to delete app cache.

You can restore from iTunes to remove it, as it's not backed up. If you run out of space on your device, iOS will automatically remove the cache.