Ohio guy,
Yes, it's true that you could mess up a gun by using a dremel tool on it. It takes experience to be able to polish a gun in that manner, just as it takes experience to use a buffer on a car.
You can get very good results just doing it by hand, if you're patient. I've done a couple and they've turned out pretty well.
What you want to use is Mother's Mag Polish and a couple of soft cloths. Expect to spend a few hours the first time you polish it. Then, I always put a good wax on my guns, whether stainless or blue. It really makes a difference. A lot of people use Renaissance wax, and it's good stuff. I used to use it too. But, now I'm using Collinite wax.
On the guns I've polished, I've repeated the polishing session each time I cleaned the gun. Each time, it's come out a little bit better. That's not to say you can't just do it all at one time. However, it's quite a chore when you're doing something like that by hand. Thus, I suggest polishing over a period of time.
As far as hurting the value.. well, if it was a gun that was a limited production, I don't think I would do it. But, there's a lot of 686's out there. Not knocking your gun; the 686 is a really good choice! But, I think that since there's so many of them, you would actually enhance the value a little.
When I sold one of the guns I polished, the fella who bought it was drawn to it to begin with by the looks. He said he just had to have it, and bugged me for months to sell it to him.
If you decide to do this and want some detailed help, let me know and I'll try to help you. Just email me through this forum.
