[Windows Phone 8 Development and Hacking] GoodDayToDie:
Known issues:

Many locations that we nominally have access to don't actually grant *delete* access, only read and write/create (yes, NT tracks permissions for Delete separately from Write). Thus, a lot of files that you'd like to delete might not actually go away. (Sadly, this includes the EdmCache\Lib folder mentioned in the thread linked above). I'm working on it!

Should be fixed as of 0.2.0, if you have a Samsung phone and an SD card!

Many locations set the Read-Only flag on their files, making them un-deletable even with move-to-SD.

Should be fixed as of 0.2.1, which removes RO flags either in-place or acter move-to-SD

The app startup is pretty slow. Well, it's actually fairly fast, but it seems slow because the entire structures of all relevant directories are traversed before the UI is shown. I will move that to a background/async thread "soon".

Viewing the files for some locations (like the TIF folders, which often have hundreds or thousands of files) will cause the app to hang for a long time while it tries to format kilobytes of text into a MessageBox.

As of 0.2.0 this problem should no longer occur, as the messages will be truncated before being displayed in the MessageBox.

There's no way to change the list of locations. Well, not short of re-compiling the app, at least. I'll move them to external storage soon.

Features I want to implement:

Filtering (especially for specific folders) to files older than a certain date. This is actually already supported by the app; there's just no UI for it.

Adding additional locations for cleaning out files from, and removing locations too. Ideally, these would persist across runs of the app.

One button to select (or clear) all locations.

Option to hide locations which have no files of interest (just to make the list smaller).

Ability to edit a given location's filters (filtering on filename patterns is already implemented, but again, there's no UI for it). This should persist too.

At some point, the ability to select (or de-select) specific files or folders for deletion, in case the filtering isn't fine-grained enough. This is pretty easy to add; I just hate writing XAML.

While I'm at it, the ability to delete directories might be good. Currently this tool only deletes files.

More detailed errors when deleting a file fails. It's *usually* ERROR_ACCESS_DENIED, but it could be something else (like the file being in use by another program).

An option to move files to the SD card instead of deleting them. This would save space while providing the ability to implement an un-delete. True un-delete would require some kind of log or structure to the moved files.

Speaking of logs, I really should have the app generate one. Again, the basic stuff is already there; in fact, it generates *too much* text, so much so that I had to make it truncate MessageBox contents at about a KB.

Option to report file sizes in units based on powers of 1000 or powers of 1024 (currently it uses powers of 1000).

Internationalization would be good.

Possibly, at some point in the future, the ability to check (and clean out) the storage of other apps. You can clean them by just removing (and re-installing) them, of course, but sometimes that's a pain, and a more specific filter may be good.

Possibly an in-app update notification when new versions come out...