I scuffed my Apple Watch 5 Aluminium Space Grey slightly. I ordered the Birchwood Casey Aluminum Touch-up Pen. It is fantastic. It has not totally colour matched the mark. But what it has done is significantly dull and blacken the exposed Aluminium. I can’t recommend this enough. I wish that I had taken a before photo. However, I have taken an afterwards photo and circled the affected area that was bright silver before using the pen.