What car is that ashtray from?? It looks remarkably similar to my mitsu eclipse ashtray.
Any-hoo, if I were you I would go to ebay and purchase another or 2 extra ashtrays and practice cutting with a dremel and molding and shaping that piece till you are comfortable. that way you will always have the original to stick back in when you sell the vehicle. I have purchased duplicate pieces of all my molded stuff for that very reason, knowing i havent ruined the orignal piece.