I just cleaned the inside of my G5 iMac the other day. I used a vacuum with the edge attachment. I didn't touch the computer at all, kept the attachment an inch above the computer and sucked the dust out of the few spots that had some built up. I made sure I kept my hand grounded to avoid any possibility of static. The inside of mine has never really gotten dirty. I still take it apart once a year to clean it anyways. BTW, I have a dog, cat and wife who hates to clean.