Make Your Own Envelope Glue!
What you will need:
6 Tablespoons white vinegar
4 oz unflavored gelatin (in packets or bulk form)
1 Tablespoon flavoring such as vanilla extract, mint, almond, etc.
In a small saucepan bring vinegar to a boil
and dissolve the gelatin in it. Remove from heat and stir in flavoring.
Brush a thin layer on your envelopes. Let dry. Store
the unused portion in an airtight container. It will gel when cooled.
Re-heat when you need it again.