"The Jenson's Swirly Q brush is designed for scroll striping and script lettering
with enamel based paints. Scroll striping requires thinner paint, if mineral spirits
were to be used the paint would run easier. I recommend using a slow
drying automotive reducer for enamel based paints, these can be purchased
at your local autobody supply. Clean brush thoroughly with reducer before
and after each use (do not use lacquer thinner!).
Be sure to store your brush in mineral oil between uses." - Gary Jenson