Freezer

• 1). Place a sealed envelope into the freezer for two to three hours.
  
  
• 2). Run the blade of a sharp knife gently under the flap of the envelope.
  
  
• 3). Open the envelope gently.
  
  

Microwave

• 1). Place the envelope in a microwave.
  
  
• 2). Turn the microwave on for 20 seconds.
  
  
• 3). Remove the envelope from the microwave and the flap will open when nudged.
  
  

Steam

• 1). Pour several inches of water into a large pot and place it on high heat.
  
  
• 2). Wait until the water is at a rolling boil.
  
  
• 3). Hold the envelope over the steam until the glue softens.