Cleaning vinyl seats

So I am about to pull my boat out and do a detailed cleaning to it. I want to clean the seats. They look a little dirty probably from the several camping trips last summer. I tried using Meguirs boat vinyl cleaner and while it cleans the surface the vinyl still hade a dirty look to it. I am familiar with the Mr.Clean magic erasure in combination with the Totally Awesome cleaner form the dollar store. That works incredible but I found out just how abrasive that combination was on my last boat when I started un-earthing a patch job in the upholstery. So, I am not sure I want to go that abrasive. I am also uncertain what that would do to the trim vinyl that has a light grey color to it. Does anyone have anything in between that will get the white back without the abrasive nature?

Also, I have a spot on one of the seats that has a dime size area of tree sap on it. Probably go there from being parked at the campground. I am trying to figure out what to use to get that off without damaging the vinyl.

This is on a 2005 Sanger V215 if that matters, not sure if the vinyl really differs that much across brands.