Finally got some C&D today and its official as far as I am concerned that only abrasive pads remove true track marks. C&D is just another surface cleaner (citrus based cleaner gel) that doesn't magically remove oil from deep in the ball (towel had nothing on it after cleaning).
Clean'N Dull has been used by many on this forum for years, I myself have used it since the days when it was under the original A.P.P. banner.
It is one of best cleaners on the market and one of the few that penetrates and removes oil (oil track lines as can be seen below) from the cover of a ball.
oil track lines soaked into the cover:
What it does not do is remove track wear, that has to be removed by abrasives.
(The name is misleading, a lot players think it means it dulls the ball like a abrasive but it doesn't. The original marketing just meant it to mean it leaves dull balls dull it doesn't change the surface.)
Clean'N Dull Used with a proper ball maintenance regimen can eliminate or at least reduce the need for oil extractions.
Using it once a week is not a hard and fast rule. How often you use it, depends on the conditions you bowl on and your personal cleaning regimen.
Yes it's expensive, but a little goes a long way.