Best way to clean speakers

Micro fiber dust cloth.

Gravity , thats funny .

Good call Drdennis, I'll just stick to vacuuming.

Lambswool "feather type" duster is what I use and just to clarify it is like a feather duster no flying sheep were killed to make these. I found mine at a lighting store.

Makeup blush brush. Use the same type for cleaning the surface of CDs and DVDs every time before inserting into player. (you can get your girlfriend or wife to buy a nice one for you. the very short, really fat round ones are super.)
The brush is very soft, really fat, and easy to use.
I don't have cone speakers anymore except for the 5.1 setup. but I used to clean my B&W 805s with the brush and it worked very well.
As for tightening down woofer screws, yeah, a littl goes a long way. A gentle even pressure setting all around on those screws.