abstract
aged
area
background
bolt
brass
bronze
brushed
copper
damaged
door
empty
factory
gold
golden
grunge
grungy
hard
illustration
industrial
industries
iron
metal
metallic
old
oxidation
oxidized
panel
peeled
plate
reflection
rivet
rough
rust
rusted
rustic
scratched
screw
shabby
shape
silver
space
square
steel
strong
texture
worn
worn out
yellow
zinc