A blending medium for colored pencils. Gamsol is a brand of artist-grade odorless mineral spirits, which is packaged into a convenient, sponge-top dabber bottle. This 'magical' liquid results in a pretty, almost watercolor-like look since it essentially melts the pencil lines and erases their grainy appearance. Simply color in your stamped image with colored pencils, and apply Gamsol using the blending stumps.
Note: this technique is made for regular colored pencils, not watercolor pencils. It is easy to learn and really makes a huge impack in your artwork.