I'm very inexperienced at painting and want to do it right, so I've been reading up on the subject. I've seen 'sanding sponges' mentioned. I have something that I think is a sanding sponge - a sponge wrapped in sand paper? One article I read in this month's issue of TOH says to wet the sponge. Do I really soak it, squeeze it, then sand w/a very damp sand papered sponge? Just seems weird to sand w/wet or damp sand paper. Why is it wet? Does it work better than dry? Thanks for any advice.