Never used a Nokia, presume that's what a n72 is. 2 mega pixels? You'll get noise, you need to experiement with the distance/subjects until you perfect it try not to go to full zoom, keep in mind it's not really a real camera and it has a bad rating for photo quality.
http://www.ciao.com/Nokia_N72__Review_10001091As for emptying your card can you not format it on your phone? If it's one that you plug into your PC just go to the drive and delete all the pics.
Sorry not much help but we do have a few tutorials on how to remove noise, and theres plugins that you can buy but in reality you'd be better of buying a small camera.