Q: My i tunes cards only have a bar code, and only a 'bar code' number' underneath.   Not a serial number beginning with letters.  They may be old but are unredeemed.  Is there anything i can do?

I would like to redeem some itune cards.  They only have bar codes and bar code numbers.  they don't have a serial number.  i tried offering the bar code to my imac camera but don't know how to take the picture or whether if i manage to do that it will help?