When pinstriping, using paint thinner to thin your oil based paint as you stripe is a good way to keep your paint properly flowing off your brush.
Using gloves I can always make sure the paint is properly loaded and thinned in the brush by running my fingers across the hairs with paint.
I like to use a 3 part mineral spirits wash when cleaning my brushes after striping and before I stow away.
Use Mineral Spirits to preserve your brush between uses.
Watch the YouTube tutorial here: