So here's my 2 cents. Hope I don't piss everybody off.
Lots of good ideas, but be forewarned you are venturing into the land of permanent change. The nickel kisses are very similar to the consistency of your stainless slide and your biggest problem is they are on a matte finish. By definition (not Merriam Webster); A matte surface is a dull finish of random contours of similar consistency... any attempt to remove the adulteration by hand will change the surface consistency (ie: leave witness marks). Sheepdog's method will most likely yield the best results (BUT DON'T USE A HAMMER) as it will leave marks too. Use a leather mallet or a block of wood and tap lightly! The trick here will be finding sandpaper of similar texture, most likely 3M corundum in 220 or 320, you have to be very-very careful not to rub when placing the sandpaper.
The original surface is applied by beading... sandblasting technique using glass bead, there are a variety of methods to re-apply or repair this type of surface. A cheap sandblaster kit from harbor freight (they also sell small bags of bead too). Another alternative is baking soda and WaterPik toothbrush. Making a slurry of baking soda and water and running it through the waterpik, the trick here is getting enough soda in the water to effect change on the slide and not plugging up the watepik. I have repaired several scratched and lightly damaged slide tops by rebeading. Use masking tape to cover the satin or machined surfaces. Start your beading approximately 10 to 12" from the surface and work your way in until you achieve the finish you want. If it becomes necessary (because it won't blend) you can rebead the whole slide top. Yes in most cases a blast cabinet is used but you're not doing this on a regular basis, so it's not necessary (safety glasses ARE!) and yes you will need a small cheap air compressor.
Here are few links to cheap tools to do the job.
http://www.harborfreight.com/gravity...gun-93221.html
http://www.harborfreight.com/portabl...kit-37025.html
Some different grades of media.
http://www.harborfreight.com/rock-po...ves-30956.html
http://www.harborfreight.com/50-lbs-...dia-65929.html
I hope this helps.