Borrow a dremel. Tape down a cloth to cover the keys, ports, fan exhaust, and the monitor. Go along the edge with a grinding tool on low speed. Go along it again with a sanding tool. Finally, buff it. (All cheap parts in the default kit).

Wear a mask.

Also, the amount of grinding necessary to get a smooth edge is not much at all. This is a quick job, and leaves the same grey color.

Finally, there are covers that remove the hard edge.