Dremels and power tools are not always a safe option for cleaning, especially if you are not real familiar with them and when it comes to chambers of any kind, most particularly. If you are comfortable with using them, please be careful with the materials you use or you can quickly oversize dimensions to dangerous levels. I never use dremels or power tools on bores or chambers, as taught to me by a credible gunsmith, unless you are in the business of resizing or professionally polishing them.

I have found Birchwood Casey's lead remover cloths to be very mild and very effective for the removal of lead rings in cylinders, and works especially well on stainless revolvers; it will also remove the rings around the forward face of the cylinder and around the forcing cone easily. You can then polish the whole weapon with them for bit of extra shine, but it won't take scratches out. Works great on bores too. I recommend some precleaning with Hoppe's # 9 and a brass brush, unless you have a finish easily damaged by it; Shooter's Choice is a good alternative. Here's the Brownell's site for the cloth, I highly recommend it as a non-abrasive alternative:
LEAD REMOVER CLOTH - Brownells