Welcome to Autopia Forums, Gary !
What exactly are you working on in this Interior? Its plastic, but is it the chrome plastic, colored black plastic, wood grain plastic ?
Is it across the front of the Dashboard, around the console, a long strip of it along each door, etc., ?
On as many places as possible, you would want to make straight back and forth motions when using anything, so as to not make/add swirls that show up later..
The only product I ever use to make those pieces better (except the dashboard gauge plastic faces - try to not touch them very much), has always been Zaino All-In One - Cleaner Polish Protectant..
It`s not too cheap and one bottle if this is all you use it for will last forever...
It is a very mild abrasive, emulsifying cleaner, that is good at clearing up some scratches, and it leaves a little zaino sealant on the surface after..
I only use a very, very, soft, short nap microfiber on Interior pieces that look like they could use some help, and I rub it in straight lines, let it dry and carefully wipe it off..
Dan F