I belong to a Yahoo Group called Textile Challenges, and this month we were challenged to 'decorate' some thin card tags/labels, that Carol, our Moderator, supplied. This is what I did with mine. First I cut them down to 2" wide! Then I crumpled brown wrapping paper several times, laid it out and ironed fusible web onto one side of it. I then laid out the tags and ironed them to the other side of the fusible web. I cut them out, recut a shape into the top and rounded the bottom edges, then painted the crumpled side with a light coating of gesso. When dry, I painted each tag with acrylic paints, straight from the tube, quite quickly before they dried. I also painted the back of the tags in a similiar manner. When dry I rubbed them over with a Markal/Shiva stick, then with a cloth rubbed my finger over the surface quite hard to rub the wax in as much as I could. I also did this with the backs. Finally, using a sponge brush I painted over the surface with a purple 'ink' made from Procion dye. 
This just shows one of the tags, and a back. This was an experiment, and the magic bit for me was when I added the 'ink' last of all. It coloured all the cracks I had made (on purpose of course!) and I was well chuffed with the result.