Testor Metalizer....

The best thing I have found, and admittedly I don't use a lot of it, is a cotton buffing cloth for buffing cars. I've tried Q-tips to no avail. I've used buffing wheels in Dremel tools (at low speed!) and that didn't work. I've used the rubbery side of very fine grit sanding sticks, and that works pretty well.

If anyone has any other ideas, I'd be interested as well.

Use different things for different depths of sheen. If you use Q-tips, use soft ones and make danged sure you dont let the stick come through because it will draw marks all over your beautiful NM paint job that will not buff out. Toilet paper works great. Foam makeup applicators also are very good for delicate buffing. But again, watch out for the stick. Cotton balls leave lint on yr model that's hard to get off. You usually dont see it until it is sealed in with an overcoat. Use squares of torn up old tee-shirt for a good shine, especially on the more robust metal finishes like SNJ, which I highly recommend. I wish I had some right now, but can't find or afford it. Hope this helps a little. Just use your imagination, and remember, NM finishes are very fragile until they have been fixed in place.
By the way, I still have a tube of Rub n' Buff, but nobody seems to use or recommend it any more. What are the drawbacks? It gives a beautiful shine, but I know it's made with a waxy base that would make it hard to overcoat or decal. What's the dillyo on this stuff?