Using a Dust Cover on my PS3

Hey,

I just got my PS3 yesterday, ALLRIGHT!!.......anyway, I bought a 16'' x 24'' microfiber cloth for a cover/dusting cloth. I only cover it once it is off. Is this bad? Will it hold any heat in that should be releases after the console is off? I am assuming that's a no because once off, the fans stop so there is no air current that would be blocked. Also, if it is fine to cover it, which I think it is, can it be safely covered while the PS3 is "off" but the standby switch is still on?

-Thanks

Thanks for the replies. The cover I use covers the whole thing, vents and all. That being said, when I cover it, the console is off.

-Thanks