If you're confident, you could do with an xacto knife too, but the file is more forgiving. Remember, it's always easier to take material off than it is to put it back on.
Agreed, I'm really impressed. After seeing my own bucket and thinking I did a good job, I'm getting more and more critical of my own work seeing other people's buckets.
For small silver details (like the scuffing on the mic tips), I like using a silver metallic sharpie. Works great, easy to handle and permanent. I've been using them for years (all three metal colors) to add small details to model ships, but found the silver works perfectly here.