Used paint thinner to clean my foam filter and then used 2 stroke mixing oil (the manual says engine mixing oil, is this what they mean?) to wet it. I also applied some standard white grease to the mating surfaces before installing. This was my first cleaning and I need to know if doing it this way is going to do any damage. (brand new 2000 model) Also, anyone out there who has not installed proper rad gaurds, I would really recommend it! Second ride with my new bike and I managed to bend and crack the outlet valve on the main rad. Luckily it was repairable as a new one apparently costs $500 canadian. Got rad gaurds on order ($130), and I'm sure they'll be a good investment.