There's a tutorial on how to do this safely. YouTube homemade bowling ball oven

Max safe shell temp = 125F

I have always used the dish washer without the drying cycle on. For me there is less chance of a catastrophe than using ovens or homemade heat producing boxes.

If my better half caught me putting a bowling ball in the dishwasher my bowling days would be numbered, if not gone forever!
That's why I bought a NuBall bowling ball oven 4+ years ago. I have baked (@ 125 degrees) many balls for myself and friends and have never had a problem.

 
LOL, I can relate!
 
The NuBall works and it's safe. There will always be those that insist on home remedies, but no thanks. 

I have a Nuball and have yet to get a drop of oil out of any ball I own.  I've used it at lest 10 times and so far nothing.  I wonder if the wet methods - bucket of water, dishwasher... do  a better job of penetrating deeper into the ball?  I have a No Rules Pearl that acts like it's oil logged.  I didn't get anything out of the Nuball (still acted like it was oil logged after), so I'm going to try the wet methods next and see what happens.

 
I have the exact same experience using NuBall with my own equipment. I've never extracted a drop. BUT, I wipe my covers between shots, and I do clean my balls immediately after use.
 
A few weeks ago, my teammate was complaining to me how his Track Precision had lost much of his pop. Hitting it with Abralon wasn't helping much anymore. I asked him what he was cleaning with, and he looked at me with a blank stare.     So, no cleaning of a high performance ball after several months of use.......


I took his Precision home and put it in my NuBall. The cover was wet within the first minute. It took 4 hours to completely bleed out all the crap that absorbed into the shell. After the process was done, I applied a fresh 500/2000 Abralon treatment on the spinner to bring the ball back to NIB condition.
 
It's a beast again. NuBall works if a ball has been badly ignored. Maybe the wet methods will work better in more mild situations. 

I use The NuBall.

Some bowling balls soak more oil in the cover stock. Some will not sweat or sweat as much. Some will seem like a flood gate of oil has opened. I clean my bowling balls after every set, my dad does not. My dad's bowling ball, when I put it the NuBall, will fill the tray with oil.