If the scratch is a surface scratch, the 3M aluminum pollishing and sealing compound will remove it. If it is into the aluminum then you will want to start with 220-400 grit sandpaper depending on the depth. Start with 400 and if that is going too slowly step down. Then follow with 400, 800-1000,
1500, then 2000 then back to the polish till it matches. If it is already too polished and does not match go back to
1500 then lightly polish. You can then clear coat the repair if you want. On the 1000 and up sand with the "grain" (the roll direction) of the aluminum.
If it is creased also and the crease bothers you you'll have to remove the rivets and attempt to smooth it from the backside or replace the panel.