Here are three mail art postcards, all including handwriting, and all using up scraps of this or that.
This bird postcard was made by painting a background (including the blue blob I later turned into the bird) and pasting strips of handwriting practice paper around it.
Next, I covered my cardboard surface with scraps of handwriting practice paper and glued on a little drawing. Voila! Done.
This card featured a painted background, letters stenciled on, and then some paper scraps added. Plus some scribbling into the paint.
People, save your scraps. They are useful.