I followed used tea bag lines with acrylic paints until an image started to appear. After 10 minutes I saw a bear, but then it quickly became a dog. The red/purple color is from an herbal tea bag that bled into the regular black tea bags while drying in a bowl. The highlight in his left eye was actually a small tear in the tea bag paper, but it worked. Once done, I tore way the straight edges and mounted it on a sheet of hand-made paper. Mod Podge or Matte Medium is good for doing this.
Sometimes the plain sheet of paper I use to protect my desktop from paint seeping through thin tea bag paper is as interesting as the original!