from what I can incur out of the SharedPreferences documentation, I can update a preference, add one or clear all preference values in a shared preference file.
But
you could try deleteFile to delete the sharedpreferences file in your app's private storage.
If you just want to delete the contents but not the file, calling .edit().clear().commit() should do it.
.edit().clear().commit()
If just you want to delete one preference, calling .edit().remove("key").commit() should work.
.edit().remove("key").commit()