The phrase "rusty metal" refers to metal that has been exposed to water or oxygen for a long time, causing a reddish-brown substance called rust to form on its surface. Full definition
Being heroes, they plan to overthrow their demon - squid robot overlords and free humanity, so they can all live in rusty metal buckets and eat gruel. (rottentomatoes.com)
As Cucchiara silently looks over the room, Garcia starts pulling bits of rusty metal out of his pack. (discovermagazine.com)
is the word «peace» spelled out in rusty metal letters. (lovegrowswild.com)