how to get different faux finishes?

Hey folks!

Stepping out of my comfort zone for a bit, and helping a nephew with a cosplay costume. My question is, how do I make a cheap plastic toy squirt gun look like cast metal? I made the flat parts look machined by using aluminum paint and lightly scuffing it with a scotchbright pad, then sealing it with clear gloss, but I can't get the rest of it to look right. Any pointers?