How to delete ALL FILES in a specified directory on the app?

NSFileManager *fm = [NSFileManager defaultManager];
NSString *directory = [[self documentsDirectory] stringByAppendingPathComponent:@"Photos/"];
NSError *error = nil;
for (NSString *file in [fm contentsOfDirectoryAtPath:directory error:&error]) {
    BOOL success = [fm removeItemAtPath:[NSString stringWithFormat:@"%@%@", directory, file] error:&error];
    if (!success || error) {
        // it failed.
    }
}

I leave it up to you to do something useful with the error if it exists.