To add to the above, light or heavy scratches in a blued gun are forever and cannot be "buffed out". The only way to repair them is a total re-blue of the gun.
All metal polishes, even fine ones like Flitz are abrasives, which is what a polish is.
Any attempts to polish out scratches will only thin or even remove the bluing, depending on how hard you rub or how often you use it.
The best ways to take care of the finish is to keep a thin coat of a rust preventing cleaner-lubricant like CLP Breakfree on it, or to use a wax like Johnson's Paste Wax or the excellent Renaissance Hard Carnuba Museum Wax...... NO CAR WAX.
The CLP or wax will clean dirt from the surface and protect it from corrosion.
