I'd watch youtube videos about LCD replacements as that procedure would let you clean this.
-> Examples at http://www.youtube.com/results?search_query=youtube+dell+inspiron+lcd+replacement
About a hour job shown at http://www.youtube.com/watch?v=q7JMgc0poHw
Can someone tell me how I can remove the dust behind the screen on my Inspiron 1720? It is very annoying, never had a laptop do this before. Thanks, Bob