How Do You Open a Sealed Envelope in the Microwave?

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Updated August 17, 2022

If for some reason, you want to keep your mail looking fresh and new, you may ask, “how do you open a sealed envelope in the microwave?” The best microwaves offer a safe place to heat, defrost, or reheat food. Additionally, they provide heating for hot packs when you are sick. However, certain materials should not enter a microwave while it runs for an extended time, including cloth and paper, as they are not microwave-safe. If you want a quick meal to make in the microwave, check out how to make pizza in a mug.


  • You should not attempt to open an already-sealed envelope in the microwave for an extended period because it can catch fire due to the heat.
  • To secretly open a sealed envelope, you may use a tea kettle’s steam or freeze it in the freezer to separate the adhesive part of the envelope.
  • Steaming the envelope open requires a tea kettle with boiling water, hand protection or pair of tongs, and a letter opener or other tool.

Opening a Sealed Envelope in the Microwave Oven

When you try to open mail without leaving signs behind that it’s been opened, you have a few options that could break the seal, including steam or freezing. First, however, you should avoid trying to open one in the microwave. This also includes OTR microwaves where a fire could break out quickly.

The theory behind this method relies on the same principles as steam opening. Theoretically, you would place a cup of water in the microwave to produce steam to open the seal. Unfortunately, envelopes and other paper products combust under exposure to high heat for an extended period. If you have trouble with your microwave, you might want to look at an article on a microwave making a crackling noise when not in use.

Insider Tip

Placing an envelope in the freezer may cause the seal to break.

How to Open an Envelope Using Steam

  • Tools Needed:
    • Tea kettle or pot
    • Water
    • Cup (Optional)
    • Pair of tongs or heat protection
    • Flat, smooth tool, like a tongue depressor, butter knife, or letter opener
  1. Fill a tea kettle or pot with water. You can use water of any temperature, but use enough water to fill the kettle at least halfway. If you choose to use a pot, make sure to fill the pot at least a quarter of the way. You should consider this step the most crucial since it provides the basis for opening the letter.
  2. Ensure the water reaches a boil. If you choose the teapot, steam will shoot from the spout when the water boils, offering a quicker version of this process. For a pot, you should tell it’s boiling as the water starts bubbling. Either way, you want to fill either substantially as evaporation happens to water as it heats.
  3. Grab your tongs or something to protect your hands while they pass through the steam. If you don’t have either, you may end up burning yourself on the steam. Please, keep in mind that steam rises from the boiling water and contains some of that heat.
  4. Use your tongs or protected hands to place the envelope in front of the steam. You should hold it there for about 20 seconds. Don’t try to hold it there longer since this potentially damages the mail. As you do this step, you loosen the adhesive seal on the envelope.
  5. Slip your butter knife or letter opener inside the envelope after removing the mail from the steam. Ensure that your tool is warm to avoid cooling the glue in the seal. Most envelopes include small openings at either side of the top of the flap. This opening allows you to open mail easily.
  6. Lift the envelope flap without forcing the opener through any portion. If you reach an area that sticks more than the rest, put it in the steam’s path again. Once you have the envelope open, you may remove the mail from inside.
  7. Allow the envelope to dry completely before replacing the mail. In doing so, you reduce the chances of the envelope wrinkling. When you return the inserts, be careful not to force them in.
  8. Use a glue stick to reseal the envelope and place it back in your mail pile. This process should allow you to view the mail before anyone else.


Microwaving paper may start a fire, but you could open mail using steam from a tea kettle or pot.


How do you tell if your mail has been tampered with?

If you look at your envelope and see tears or wrinkles that surpass the amount you suspect, your mail may have undergone tampering. Additionally, you should notice if someone resealed the envelope, especially if they used tape.

What is the easiest way to open an envelope?

The easiest way to open a sealed envelope in secret is to stick it in the freezer to open the seal, called the freezer method. However, this option takes more time than the steam method.

Can you open a sealed envelope in the microwave?

No, you should not try to open a sealed envelope in the microwave. You may open the envelope, but envelopes and other paper material remain flammable when exposed to high heat.

STAT: As of 2017, the average American spent well over 100 dollars per year on small appliances such as microwaves, toasters, vacuums, and coffee makers. (source)