Looking for suggestions for products or methods to treat exterior plastic cladding. I've got a 2011 Subaru Outback. I just usually wash these parts with regular shampoo, but after about a year, it looks like they need a little something like an LSP. I know a wax is not likely to produce the desired results. I'm not looking for shine...I'd prefer to keep the finish the factory matte appearance, but would like some protection. Anyone have any ideas? Thanks!