Anonymous15 I feel like maybe it’s not the back panel, there’s a gap between the transparent panel and the borders of the phone and it catches a lot of hand dust, you can use something thin to scrape that dirt off and clean it up
vovan-v SakshamYadav_u4PfW8OjfC try to reach Nothing support team or Nothing store were you bought the phone maybe they can replace it if the phone is on warranty.