I have a co-worker using my coffee mug at work. I want to make him stop without sounding like I'm being picky. I have tried making the point indirectly that the cup belongs to me but he still uses it.

Our cleaner cleans the cups and puts them on a tray in the kitchen area, he usually arrives in before me too so I can't just nab it before he gets here.

What would be the best way to go about this, as I said, without sounding like I'm being fussy.

Edit :-

I got to work 30 minutes early and..

I got my cup back!