Buy a repro (assuming they are made, they are for '69). Failing that, have the original replated, the solution that I endorse for many of the detail items on our cars which result in a factory new appearance because after replating a good core, they basically are.
Remove the ashtray from the car. Cut or drill the rivets out that connect the ash tray to the fascia, separate the outside door from the inside ash tray. Bead/sand blast the sections. Clean then repaint the ash tray with spray gray or an aluminum/silver paint similar to the original color and repaint the outside door the color of your dash if required. Rivet the two pieces back together and re-install.
I think the Mustang unit is a different size than the Cougar, shorter I think.
I agree with C7XR7, the only thing I would add to his comment is to replace the lighter assembly when done with the refinish. I did mine so I would have good contact for my cell and IPOD adapters. The cigar idea is funny Dale. It reminded me of my neighbor when I was growing up, he always had a big cigar chewing on it.:smoke: