Ahhh yes. The old red jeweler’s trick. I had forgotten about that. Red jewelers rouge crumble/ground up in a can of brass. Shaken not stirred… A Marine’s fast track to highly polished brass. A trip down memory lane.What I use for metals which do not corrode when in contact with iron/steel (with dissimilar metal corrosion such as seen in steel screws in aluminum), is red jewelers rouge on an oiled cloth, which is fine enough it does not scratch gold, but which will also put a mirror polish to steel already at a fine finish, also to polish and deburr knife edges on a cardboard or leather strop. Given the everpresent dust around here where no flat surface is truly non-scratching, such work on the 681 would be a waste of time. One of my early motivations on my wicked mex carry ways was to (totally successfully) dodge all the firearms finish wear from holsters with their inevitable embedded grit (and attack by tanning salts with leather). My daily drivers stay nearly new appearing, including my 1976 Blackhawk which would pass for a dealer case sample with light handling marks, and despite untold thousands of rounds. I put more marks on my guns through cleaning whoopsies than from carry, but it IS important to clean under grips when sweating buckets in more humid climes such as my semi-tropical Gulf Coast origins where stainless rusts with regularity and blackpowder rusts/browns guns as you shoot.