MICRO FIBER CLOTHS
A couple people have suggested these, on various groups. I went to the "as seen on tv" websites, and found the cheapest set overall. They all had the same item, just others asked $5 more, or others charged $10 for shipping, compared to $4, etc etc. It pays to shop around.
I will admit that these things are great for dusting. They get into cracks and crevasses much better than expected, and they abosrb the dust, instead of just smearing it around.
Anyways, back to coins. With my finishing technique of silver brushing, soaking in rubbing alcohol, using a 3M radial brush, renwaxing- these cloths don't really do much. On some coins, you can tell that the cloth is absorbing some dirt, by the little smear on the cloth. Visually, I can't see a difference. On most coins, I see no dirt on the cloth at all. It does seem to shine the coin up a little more.
Now, if I remove the 3M radial bristle brush step; before Renwaxing, these cloths do pick up alot of dirt. My radial brush is removing the dirt pretty darn well, and I like the sheen. If you're wary of using power tools on coins, then these may be a good tool for you.
Before/After photos really don't show the difference- since most of the change is in shine... so I'll bypass the photos today (and I'm feeling lazy). But these little cloths do work well.
One photo I will add is this 1993 S Proof quarter that someone handed me in change the other day. It was tarnished, had some kind of debris on it- a normal looking quarter found in change pretty much. I noticed a bit of frosting on the eagle shining through and took a better look at it. Why anyone would use a proof quarter as a quarter I have no idea. Perhaps it's the same guy that used a silver eagle for a dollar a couple weeks ago.
Anyways, I didn't take a before shot of this unfortunately. I didn't expect anything to happen honestly. I simply rubbed the coin for about 30 seconds. There was a drastic difference in the appearance. Now, you can tell it is a proof. Unfortunately, it has been marked up a bit on the obverse. This was not due to the cloth.
The cloth cleaned up the light dirt and debris, and brought back much of the proof shine:

3/17/06
After much more use- I would recommend these. I use the cloth after the 3M radial brush. It seems to shine the coins up a bit more, and on some coins, I can tell a difference in missed dirt.