I was wondering the same thing and did a little looking around and from what i read everyone says do not try to clean them just replace them. Only way i heard to clean them without damaging them is with a torch or with electric parts cleaner. I heard brake/carb. cleaner is bad for them. I never tried either i just replaced them so i dont know if it works or not. I would just bite the bullet and pay the 40$ apiece. Just my opinion.