Great machine to get ... but not so great if it is unbearable!
First of all ... is there a smoker in your guild who would adopt the machine?
Or at least could give it a test drive or six, to ensure it is worth fussing with?
Agree with the others ... contact a local sewing machine repair shop and ask for their advice.
Be careful ... that anything you "try" does not damage your machine in other ways.
I would fear the smell is embedded in the plastic and your efforts may be futile.