Iam using this called Power Clean, helped me clear caches when I ran out of storage to upgrade iOS update
This is the only one that I've found that clears not only memory but also the cache from applications.
Not to mention Dropbox. Unfortunately the app doesn't clear Dropbox cache. Only way to do that is to reinstall Dropbox.Great suggestion. I will definitely try that one again. I still think Apple should come up with a solution to clean cache. There are apps out there that offer this but not all. Especially for apps like Facebook you really want it to keep small but it increase over time to a whopping 400MB or so.
Iam using this called Power Clean