Yes, always wash separately. Like I said, only happens with Americana, I should ad however; that its during a wipe down with Adam's Detail Spray that this happens. No, not during waxing, I only use the detail spray after the waxing has been completed and removed, and let sit for a day or so. Americana just seem a little less slick than the Z-8, for obvious reasons. Maybe its something with the relationship between the two? Wipe down with detail spray and the waffle weave towel works great though...