Think about what it is you are trying to achieve.
You have a sear with a face that was supposedly cut to a precise angle squarely across the sear.
Depending on the gun design,you may have a hammer notch,cut with similar precision in a machine.
These two surfaces should precisely mate across the width of the hammer and sear.
Do you,or OHeir,really believe you will "improve" surface finish by spinning some grit filled ball of rags over these surfaces?
What you must preserve is precise geometric form. Rags (buffs) don't do that.
Its done with precisely shaped hard stones. Generally ceramic,these days,though high grade hard Arkansas stones work well.
These stones are controlled for a square,straight stroke and precise angle by a sear jig.
I have these tools,and 20X magnification to set them up. I get my final "shine" off of a black Arkansas stone that is dressed true on a DMT diamond plate.
No rags,no felt,no Dremel. OK,I have been known to use an optical comparator and a surface grinder,too.
Rounding,eroding,washing out sear and notch geometry reduces engagement surface and tends to make dangerous triggers.
"Polished shiny" is ONLY beneficial when precise geometric form is maintained.
That is done with precise hard stones that are controlled ,not a formless buff held in the free hand