I've polished the sides, muzzle and rear of a matte stainless slide on an old Taurus PT111 Pro that I had. I used a Dremel with Aluminum oxide wheel to first remove scratches and such and then jewelers rouge on a felt wheel, then some Maguiers metal polish compound on a felt wheel for the final polish. Came out to a mirror shine with no waves in the flat sides of the slide.
"Laws that forbid the carrying of arms...disarm only those who are neither inclined nor determined to commit crimes...Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man." - Thomas Jefferson, 1776