I've used the 'generic' degreasers (Simple Green, Formula 409, etc.) as well as the true blue bowling commercial stuff (Ebonite Powerhouse, Neotac Liquid Nitro, etc.). Both types seem to work about the same. The bowling specific cleaners might do a better job, but it's tough to tell conclusively. I like the resulting feel of the cover from using Liquid Nitro, so that's the determining factor for me.
The irony is that most of the products discussed are not the answer to truly deep cleaning. For this you have to bump it up a notch and use products like Neotac's Khameleon Particle Sand High Tech Ball Restorer or Track Clean 'N Dull. Guaranteed, these products will pick up stuff from the cover that the liquid degreasers leave behind.
So use your favorite degreaser (Simple Green, F409, Liquid Nitro, Powerhouse, etc.) after each set. Then at regular intervals -- depending on how often you use your equipment -- use one of the high-end bowling specific cleaners. They'll not only deep clean, but in many cases recondition the cover.
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