You could try this ReleeS spray from jokers Russ Andrews. In a catalogue they recently posted to me they recommend spraying it on everything from cables to DVD disc trays to magically improve the sound / image from your equipment.

http://www.russandrews.com/product.a...VIPEDNCWVGMCJM

Hardly surprising at £30 for 50ml! Hang on, perhaps they might recommend rubbing it on the N900 display for a more vivid image and 'snappier response'.