Number plate too shiny!

Hi,
The new number plate for my rustoration series 2 is too new looking and looks out of place on a tatty scooter. Are there any tricks for giving it a realistic 55 year patina?
Cheers
The new number plate for my rustoration series 2 is too new looking and looks out of place on a tatty scooter. Are there any tricks for giving it a realistic 55 year patina?
Cheers