Clutch plates are used to create a connection between two metal parts, be it the input drum clutch disc’s of a 4L60E transmission or the clutch that pairs your flywheel to your transmission. When the friction material on the clutch disc comes into contact with both metal surfaces, it temporarily bonds them together through friction. The ideal clutch will have zero slippage; when it is applied, it will grab onto both surfaces and hold them in sync until it is released. The biggest problem with grease or other fluids on a clutch disc is that as heat builds from friction the grease will be pulled to the top of the material and in turn create slippage; sometimes to the point the clutch is unusable and must be replaced.
First and foremost you need to inspect and determine how bad the grease has actually contaminated the disc. If the grease was rubbed in or forced into the friction material by pressure from wiping, it is likely ruined dependant on the area and will not be worth the risk of the labor involved if cleaning is unsuccessful. If the grease contamination is lighter, and hasn’t been forced into the material, there are a couple old “tricks” that will help revive the clutch disc to save you from having to purchase a replacement.
Aside from the methods listed above the only other way to get grease off of a clutch disc is to lightly use a torch until all the grease is removed. Keep in mind if your clutch material is bonded instead of riveted, extreme heat could cause the bonding to fail. Before you opt to attempt a cleaning that may or may not work, you need to evaluate how much time you have along with the ambition to repeat the clutch replacement job again in the near future. If you can get the grease removed more power to you, but be for warned sometimes the better option is to spring the extra 200 bucks for a new clutch just to be safe. Remember even the slightest contamination can cause problems and slippage from your clutch disc.