Dissolving and "painting" with pastel pencil colour

I have just been given a set of 12 Daler Rowney Pastel Pencils. In addition to the techniques of shading, colour blending, burnishing, and lifting and scraping colour off, is there a technique for dissolving colour. For example, how do I dissolve and spread colour that has already been applied to the paper or use a brush to apply colour from a palette created on a scrap of paper? What solvent is used? Is this technique described anywhere on your website?
Many thanks for your help,
Elizabeth, Toronto, Canada