resurfacing plastic

[bradleyheathhays]

This is a pic of the top framework of my new (read used) aquarium. It's dark brown plastic framework that's been aged somehow that now makes it looks it scuffed and rough. Does anyone have a suggestion as to how I can make this look new again, that's favorable to fish living in this thing later down the road? I'm thinking a coat of maybe polyurethane would make it look better, but I'm def open to other options.

Thanks. I'm all ears.