I just wanted to chime in and say that I love using nevr-dull. I use it all the time for work and it does a good job cleaning, polishing, and protecting the tons of old door and window hardware that comes in. I especially like it because you can clean things up gradually and leave some great patina.
The stuff seems to last forever too. I found a can in my Dad's basement that had to be at least 15 years old and it still did a great job cleaning every piece of hardware in his house.