I just had to try my new alcohol inks immediately!!
As I was really surprised by the "real" rusty look, I decided to sand the edges of the card as you would do with real metal.
I used Ranger alcohol inks "Rust"- Earthtones, "Sunset Orange" - Brights and "Juniper" - Lights. The stamps are from the Artemio stamp sheet "Bugs" and the 7 Gypsies "Conservatory" stamp sheet.