Fix for discoloured stem

[Ajsnow93]

So, I ran a bit of alcohol through the stem to clean it, and a drop or two got on the outside of it and left a big discoloured stain on it. I believe that is oxidation, if I am not mistaken, and I wanted to know what is something to fix it, and bring back the shine on the stem?
Thank you guys!

 

[Chasing Embers]

Clean it with a Magic Eraser and thumb buff it with plain white toothpaste for a mirror shine.