Hot water bath is the easiest and also effective way to do it. Only needs to be done when you see a loss in reaction. Everyone has their own way to do it. Personally, I use a green scotchbrite pad on the ball(600 grit), fill my basement sink up with the tap water as hot as it can come out. Place the ball in the sink and let the water cover the ball completly up(about and inch over the top)Leave in for 20 minutes, drain water, wipe all the oil off that comes out and repeat the process until no more oil comes out. 2 or 3 times should be enough. Some put Dawn soap in the water to help with the process, I don't bother with that. Once done, let the ball dry over night, then take the ball back to factory OOB condition, in your case 4000 grit. Some just do it with the ball as it is and don't mess with the coverstock. You don't have to cover the finger and thumb holes to do this process. Just make sure it is dry before using. There are other methods that work and used by others. You can search this site for a few. Good Luck.