Whats the best way to clean speaker grills?

Vacuum cleaning with the "curtains" hose should do the trick.

I would assume that you would remove them before any vacuuming or air blowing etc. I like to use a piece of two ince tape wrapped around my hand with the sticky side out. We have two cats and this "defurs" them really well and safely. Pat gently with your hand and change tape often.

I've always removed the grills and wiped them off gently with a clean, moist sponge. It's simple to do and works very well. I've been using this method on me JSE's for over 13 years now without any problem and I don't need a compressor or vacuum cleaner... making it easier and quicker, so I'm more likely to do it!