Captain Phasma, introduced in Star Wars: The Force Awakens, has impossibly shiny silver armor. The chrome look isn’t simple to replicate with craft foam and Worbla (though I’m sure it can be done), but fiberglass definitely does the trick. Redditor TheGeeksterChief added Phasma’s sparkling finish with Molotow liquid chrome. They didn’t use the Molotow markers though since that would take forever, but they did use the marker ink. TheGeeksterChief explains:
I ran it through an airbrush slightly thinned with alcohol. The refills are best, as the pens are quite messy to get the ink out of.