If you're talking about a 1996 W210, you have to remember it's got 10 yr old paint. Color sanding isn't really designed for this scenario. Buffing, like Pete said (he owns a body shop), is all I'd do to 10 yr old factory paint.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)