Use Spray Disc Brake Cleaner to Clean ALL the Parts. Don't forget to Clean-out the Channel on the Lower Chrome Tube that has the Nylon Slider in it. Replace the Nylon Slider if the Forks were Vibrating. There are some Suspension Web Sites that explain how to add a Strip of Shim Stock in the Channel ... Behind the Nylon Sliders ... to FINE TUNE the Front End Suspension. Advanced Suspension Tuning. I've never done it.