Is there any way to clean up the cache used by WhatsApp other than reinstalling? Because lots of audio messages and voice recordings made my WhatsApp Data size much bigger (Around 700 MB).
Unfortunately there is no Windows Phone settings menu to delete the cache of 3rd party apps. You could try to delete individual (voice) messages, but of course that might be a lot of work.
The easiest way at the moment would be a reinstall.
Also, you should consider contacting WhatsApp directly about this issue - for them it should be easy to offer a appropriate function.
Unfortunately there is no way through which one can clear Windows Phone cache of 3rd party apps. This can be done by deleting individual messages but it will take a lots of time.
The only way is that reinstall whatsApp. reinstalling will clear a lots of space not full.
Hope this will help you out!! :)