I have a combination lock whose combination is etched into the sticker in the back. I didn’t do this myself; somehow I’ve always managed to remember the combination. That was my brother’s doing. But even if I didn’t remember, there’s a very easy way to break the lock. Take a look and give it a shot yourself if you have a look. I’d give it a try myself, but my lock is in the very bottom of a box, and I don’t feel like digging it out.