I use a long handled mini brush to clean the bobbin area and areas deeper inside the machine. It looks like a mascara brush, but with a long handle. Ask your gynecologist for one at your yearly checkup! My doctor laughed and gave me several to use and to give away. It goes without saying that these are clean, unused brushes.
Some makeup counters in department stores have disposable mascara brushes; ask the clerk for a clean one, but the handle will be short.