Take it from me:  When cleaning a lampshade do not use Windex...it does not clean everything, and it can in fact, make quite a mess on the surface of the shade's delicate material.  Learn from my stupidity, as I have just made the mistake of cleaning dust off of my "new" lamp with Windex and a paper-towel.  More Lessons of Life will come as I make more ridiculous decisions living my very apropos trial-by-fire (to borrow a cliche) lifestyle.