I don't know of any brick-and-mortar places, but I'd use something different, that *is* available, anyhow: artist's brushes. An art-supple/hobby place will have a lot of small brushes that are just great for touch-ups. Something like a 00 ("oh-oh") or 000 ("triple oh") will work great, and you can even get something smaller if you like.
I use these for all the things I used to use tiny swabs and matchsticks for: rust converter, touch-up paint, etc.