Hi Effy, I use Nu Finish Wax on the metal parts of my coach especially the front end and the outside storage cabinet doors! When I was driving over the road (44 years, until I retired 3 years ago) I would wax my Peterbuilt (Semi) every Spring with 3 coats of Nu Finish Wax and it would last one full year. I've tried everything on decals and from my experience Aerospace #303 works best for keeping the luster on decals. On the fiberglass I use pledge furniture polish easy to use and does a fair job. Good to hear from you again and Good Luck in whatever you choose.