Is there a way to delete only documents/data of an app without deleting the app itself? I am running out of space on my iPhone and since iOS 5 I can see the worst offenders in Settings -> General -> Usage.
Some apps while being very small themselves have accumulated a lot of data. I want to keep the app itself on the phone but would like to get rid of the data.  

Is there a way to delete the data/documents directly on the phone without deleting the app itself?
Or is re-installing the app the only possible way?
If the application doesn't provide a way to delete documents, uninstalling and reinstalling the app is definitively the best option here.