I had a bad smell when i put my aircon on, so i Went to halfords today and bought an aircon refresh anti bacteria spray, cost around £11.99, put the aircon on recirculate and full blower, set the can off and shut the doors, left it running for around 5 mins after spray stopped then Opened all windows/doors etc, then replaced the pollen filter (took me a while to find it) and hey presto, smell has gone and aircon is freezing and blows a gale into the car!!