Generaly, the iron-on coverings have plenty of shine with no help.

You can add some more shine, and seal up the seams with a spray coating of "LusterKote" This can help with preventing the fuel residue and cleaning solvents peeling the edges of the covering. (some spray cleaner mixes can peel the covering if the edges aren't sealed. "Simple Green" is one that will peel it.)

Waxes also slow down the peeling effects of some products... but the wax comes off first time you use something with amonia in it.

Never use rubbing compound on un-painted MonoKote. It will just abrade through the mylar.