If a heated light bulb can hurt your ball, then NEVER keep your equipment in your trunk of your car during the summer especially you folks that live in a warm climate all year round. The temperture will get well over than of a rejuvinator.
I understand that coverstocks will vary from manufacturer to manufacturer, but I have been using a rejuvinator since they hit the market and never had a problem with any ball regardless of manufacturer.
Use any method that you feel confident in.
I do not believe anyone on this site can honestly say that their ball has 500+ games and it reactes like it did when it was new (unless it plastic). You would need to throw the ball in a controlled environment when it was new, track the results and then perform the same test, same environment, and compare the results. AND I do not mean you throwing the ball in your league. Also, you should be close to hitting your target, maintaining the same speed and using the exact wrist action.
By the way, Brunswick recommends using the rejuvinator on all their balls. Read the maintenance section of the layout sheet.