Hot water is not only safe, but one of the best ways to revive an oil soaked ball. While it is a bit messy, about 3 baths in a large bucket of 120-130 degree water, wiping the ball dry after about 10 minutes each time will remove a lot of oil. The key is that most hot tap water is about 20 degree too cool to be really effective. You need to get water near boiling and add half hot tap water and half stove heated water to each bucket. Nothing wrong with a reviver, but hot water is inexpensive and anyone can do it at home
My ball driller discovered this method years ago. He brought back an old PK 18 shell that I had about 200 games on, and it acted like new.