I used a light coat of gesso (white paint) and then stenciled on top of that with spray dyes. After that, you fold the envelope up after writing a note or adding an image to the inside. The directions we followed were from Karen Isaacson's Blog.
I enjoyed this process so much, I ended up making over a dozen of these Foldnotes and sending them all out! I took a bunch of photos too, so I have made a little video. Enjoy -it is very colorful and moves along fast! Thanks again to Jewels & Jo. Looking forward to the October swap.