I know this is an old thread but I stumbled upon it and wanted to add a suggestion: ozone. You could rent a small ozone generator (they are often used to treat smelly cars) and put it in the same room as your kilt or any other smelly clothing. Should get rid of any nasty smells (provided the ozone gas was able to reach the smelly surface). I'm sure if you Google this you will find more detailed instructions.

Be sure not to be in the room while the ozone generator is running and air the room thoroughly after the generator has been switched off. You don't want to breath a high concentration of ozone for a long time.

I have not tried this myself but I know ozone smell removal works.