Purity seals are easy to make. Get some suitable paper, cut into strips and then into short segments. Fold roughly in half on an angle. Put a dot of glue on the back, apply to model, let dry. Take a cotton bud and pull all the fluff off one end (soaking it in water helps). Take a little ball of putty or greenstuff, put on the fold of the glued on paper, then use the bare end of the cotton bud to 'stamp' the putty in the middle, making the seal. Allow the putty to dry. Paint.