erc,
your post said interior plastics, and many were thinking: door panels, A and B pillar sailings, console plastics, etc. In which case the proper way to prep and clean prior to dressing to use a degreaser or all-purpose cleaner.
Instrument cluster plastic is another story. We see this quite often. Car washer sprays dressing all over the console, steering wheel, dash.... Wipes most of it up but the overspray was left on the instument cluster. Left unchecked, it stains.
As Chris said, try the safest route with the damp towel. If dressing is removed but staining is there, try Plexus. If THAT doesn't work, you can take the cluster apart to remove the plastic cover and use a wet-sanding/plastic polishing technique similar to extreme headlight restoration. Labor intensive, yes, but it works. Hopefully you don't have to go that far.
Good luck,
Mike R