While cleaning a ball thoroughly is always the proper thing to do, dull balls will always absorb oil, just at a slower rate. Additionally, rolling the ball on oil eventually puts an "oil shine" on the ball. Both reduce a ball's grabbing ability and thus reduce its overall performance. We don't notice it at first because it's a gradual process.
What you did is good. There is no fixed schedule for doing such because of all the factors involved. A light hand scuffing is probably all you need, IN MOST CASES. "Light" is the operative word. When you see a reduction in hooking ability or hitting power OR you see that light oil shine develop, If I were you, AT HOME, follow the Clean and DUll directions, BUT apply it with the Green nylon pad.
Now for the bad news: your scuffing, at this point in time, is
probably only a temporary fix. If you've seen a drop in performance, the ball has absorbed enough oil to affect it. Brunswick recommends an oil extraction process be performed on all their resin and particle balls, anywhere from every 30 to 90 games, in order to keep a ball's performance up to par.
There are several different processes from the Rejuvenator (a heat machine with a thermostat operated by many pro shops, a hot water bath, a dish washing machine cycle with the drier off, Columbia's CPR
(
http://www.buddiesproshop.com/products/30-Maintenance_Products/0~99999/6-Columbia_300/All/All/page.htm), Ebonite's Hook Again sytem (also performed by many pro shops.) CHeck the back posts in this forum for some details.
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"None are so blind as those who will not see."