As a guestbook, they made a photo book through Shutterfly & people wrote on the pages with
metallic Sharpie markers.
From there, it's as simple as filling in your polka dots with
a metallic sharpie — you can add - on an extra layer of metallic marker after the first layer dries if you'd like the color to be a bit more opaque.
I thought that the metallic on black look would be perfect for a Halloween diy, so here's what I came up with:
Metallic Sharpie Treat Bags.