Slinxy is right, vapor can settle on items, i have been vaping in my lounge since May last year, I have noticed the glass on my main lights gets covered in a greasy film and the display on my surround sounds looks to have condensation behind the glass screen cover, its all from excess vapor, just because you are not smoking a cig, does not mean there are not particles left behind in vapor that can settle anywhere and over time will build up and it will be the same inside a PC where your cooling fans will pull in the vapor...