RotJ Ear & key slot technique

Looking at reference pics of the ears and key slot panel, I was wondering how you guys generally handle the paint layers and the damage, because it looks almost as if the top darker gray is sanded down to the silver. Do you sand it? How do you make sure you don't sand down through the silver layer?Thx!

Thats EXACTLY how I do it, but its not just grey on there theres grey over top khaki....look at the MOM pics for reference and it takes some fine sanding and patience

the keyslots are just grey, but its faded from the top down

Yep, I used a paint recommended by AFFOFD, grimey black. Painted it onto the ears and then after it dried I wetsanded it until I liked it.