I thought I'd share something I think is kind of a neat by-product of my illustration work. When I'm in the final stages of a piece, applying the colors I create with gouache, I frequently use a scrap piece of watercolor paper as a test page before I apply the color to the paper.
I do this to make sure the color is really what I want. It also wipes off any excess pigment which will help to prevent watercolor "burps" as I call them. (You know, where the color just kind of pops off the brush and goes everywhere but the place you wanted it to go?)
It also helps me to make sure that the palette I'm working with is harmonious and evokes the feeling I want. Although I usually do a quick color study before I begin, sometimes the palette evolves as I work and the test paper helps me keep it in check.
I have been throwing them away after a piece was done, but I think I'll hold on to them for now. I have a feeling I can use them to do something fun. I love how by looking at a slip of test paper I can recall the piece and the mood of it. It could be used as a good reference down the road.