DIY Envelope Glue (Stickers too!) - The Graphics Fairy
Self Seal Gluing | Envelope Superstore
Amazon.com : Envelope Moistener Sealer with Adhesive,dab n Seal, Stamp and Letter Glue licker, Fast Drying, Non Toxic, Squeezable Sealer-Ideal for envelopes,Stamps,Letters. 2 Pack, by Executive Supplies : Office Products
How to Make Envelope or Stamp Glue | Snappy Living