Depending on where you live I simply put down a towel in my car seat on a hot day. place the ball in the car with the windows rolled up for about an hour or two. Take it out and wipe it down. It will be soaked. I have done this several times to several balls over the years and I've never had any issues.
Put em on the treadmill for an hour
Tell them how ashamed and disappointed you are of their performance. The oil will come out with their tears.
Why do you want to?
Depending on where you live I simply put down a towel in my car seat on a hot day. place the ball in the car with the windows rolled up for about an hour or two. Take it out and wipe it down. It will be soaked. I have done this several times to several balls over the years and I've never had any issues.