Well I found a very minty loose cart of Batman Returns for the NES, the odd part is the password to get to level 6-2 (practice world) is written on the back of the cart very neatly.  This could be nothing and the previous owner writting the password on the back of the cart, but I have never seen of this or thought of this before.   This could be nothing, I just thought I might check around since it's kinda off odd to find this.  Again, game is very minty and password written on cart is very neat.  Possible tester cart?  Prolly not.  I did take apart the cart and found nothing out of the ordinary.  

If anyone has seen this type of behavior (writting password on carts), please chime in.  Thanks for any information in advance.

I'd say you have an ordinary game, nothing special.  A friend of mine when I was younger used to write codes on his games and the NES itself.  

Yeah, sounds like the usual abuse some carts go through.

Thats what I thought.  I still had to pick it up since I did have it already and it's in outstanding shape, besides the writting.  $3.64 total including tax.  I will most-likely clean the writting off, just thought I'd check with someone else before I did so.

Hold on, let me get this straight.  Is 6-2 the stage where you're in the bat boat?  Because you can't lose in that level! :o There's also no way to get the password to get here in the game.

From what I've seen, though, the password function is very open-ended; you could have a code to start off with no health. :P

Could I get this password before you erase it?

The code on the back takes you to level 6-2 with unlimited health.  I have not played far enough into to it to find the bat boat?  Just a bunch of baddies.  Here is the code written on the back:

1993 14 BBBB 64

Then why did you say "practice world" ? The arctic world doesn't seem to be like a good "practicing" place to me. ;D

The reason I said "Practice World" is that is what the level description says on the screen before you start the artic stage.  I will do it again to double check, but I am almost 100% sure thats thats what the screen says.  What does your say when you start it up?