How to Tell if a Dish Is Safe to Put in the Microwave

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Learn about what materials can go in the microwave, and what can't
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Non-microwavable materials can melt, crack, or be otherwise damaged in the microwave, and they can also leak dangerous chemicals into your food, cause fires, or damage the microwave itself. That’s why we’re here to show you a quick test to see if your dish is microwave-safe. We also have expert tips from professional house cleaner Raymond Chiu about what’s safe to put in a microwave and what’s not.

Quick Dish Safety Test

  1. Fill a glass with at least 1  c (240 mL) of water.
  2. Microwave the glass and the dish you want to test together on high for 1 minute.
  3. Touch the dish lightly. If it’s hot, but the water isn’t, the dish is not microwave-safe.
Section 1 of 4:

Testing a Dish to See If It's Microwave-Safe

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  1. To test if a dish is microwave-safe, you can put it in the microwave with a cup of water to perform a simple test. Find a glass or cup that is microwave safe, and fill it about three-quarters of the way with water (or at least 1  c (240 mL). [1]
    • It’s important to use a cup that you know to be safe for the microwave, otherwise the test may not work. Glass is the best option.
    • To be certain, find a cup that has the microwave-safe stamp on the bottom, which looks like 2-3 wavy lines.
  2. Place both the glass of water and the dish in question side by side in the microwave. Microwave the two items together on high power for 1 minute. [2]
    • If the dish is too large to sit side-by-side with the cup, place the cup on top of (or inside) the dish.
    • To increase the power on your microwave to high, look for a button that says Power, Menu, or Settings.
    • If the dish begins to flash, spark, or make noise, immediately stop the microwave, then wait 1 minute before removing it with oven mitts.
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  3. After a minute in the microwave, use oven mitts or a potholder to remove the cup of water. Then, lightly place your hand on the dish in question to feel how warm it is: [3]
    • The dish is unsafe for the microwave if the dish is warm and the water is cold. A warm dish means it absorbs heat.
    • The dish is safe for the microwave if the dish is cool and the water is warm. A cool dish means it doesn’t absorb heat.
    • Note that the dish may feel warm in the center if you had the cup of water in or on the dish.
  4. In order to keep track of which dishes are microwave-safe and which aren't, use a permanent marker to label the bottom of the dish with the results of your test. Two or 3 wavy lines is the standard symbol for microwave-safe. [4]
    • You can use any labeling method you like for your dishes. For instance, you can mark microwave-safe dishes with a happy face, the letter M, or the standard wavy lines.
    • Don’t forget to label dishes that aren't safe for the microwave as well. You can use an unhappy face, an M with a line through it, or some other indication.
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Section 2 of 4:

Microwave Safe Materials

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  1. Chiu says “It’s important to read the material of the bowl prior to using the microwave if you are unsure” of whether or not it’s safe. [5] The easiest way to know that a dish or utensil is microwave-safe is by looking for the stamp on the bottom. There are typically three things that will indicate a dish is safe to use: [6]
    • The words “microwave safe”
    • The words “microwave friendly”
    • Wavy horizontal lines
  2. Most ceramic, glass, china, and porcelain dishware is safe for use in the microwave, but not all. The exceptions are if: [7]
  3. Some paper products are safe to microwave, including parchment and wax paper, and white paper plates, napkins, and towels. [9] These are often specified as microwave-safe on their packaging.
    • To make sure that no inks or dyes leach into your food, don’t use paper products that are dyed or those with printed matter, logos, or writing on them.
  4. Some plastic dishware and wraps have been made especially to be safe for microwaving, and these don’t contain plasticizers that can leach into food. As with any other dish, though, it’s important to look for the microwave-safe label. [10]
    • If you want to microwave plastic dishware, make sure it says it’s microwave safe. If it doesn’t say it, don’t use it.
    • When you use microwave-safe plastic wrap in the microwave, make sure it’s not touching your food directly.
  5. In general, avoid microwaving rubber or silicone. That said, some rubber or silicone products, like food storage containers or baking mats, are specially designed for microwaves, so long as they have the microwave-safe label or stamp. [11]
  6. There are several manufacturers out there that make heat-proof cookware that is also safe for use in the microwave. You still need to check for the microwave-safe label, but some of the companies that make these items are: [12]
    • Anchor Hocking
    • Duralex
    • Pyrex
    • Corningware
    • Visions
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Section 3 of 4:

Non-Microwavable Materials

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  1. It is not safe to microwave metal. Putting metal in the microwave can lead to sparking, fires, and a malfunctioning unit. Be sure to watch out for: [13]
    • Dishes and cups with metallic paints
    • Dishes and cups with decorative metal trim
    • Wire twist ties
    • Take-out containers with metal lining or handles
    • Aluminum foil
    • Metal utensils
    • Rocks or stones
  2. Lead glaze used to be common for lots of dishware, and is still used in many countries. Never use dishes with lead glaze to hold or serve food, because the lead can transfer to your food. Lead is extremely toxic and consuming lead is hazardous to your health. If you microwave dishware with lead glaze, even more lead can leach into the food. Dishes that are likely to have lead glaze include: [14]
    • Clay dishware with a shiny or transparent glaze
    • Handmade artisan dishware
    • Dishware with bright and vibrant colors on the inside surfaces
    • Antique dinnerware
    • Highly decorative and shiny dishware
  3. Plastic food containers that are meant for refrigerated items are often not meant to be heated, and are usually not designed for the microwave. Chiu says this includes styrofoam. [15] It also includes containers made for: [16]
    • Yogurt
    • Butter or margarine
    • Cottage cheese
  4. The USDA Food Safety and Inspection Service states that while it is safe to microwave white paper products, brown paper products should not be microwaved. [17]
    • This includes brown paper lunch bags and brown paper towels, as well as newspaper.
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Section 4 of 4:

Using a Microwave Safely

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  1. Microwaves aren’t great at heating food evenly, which is why they need a turntable to spin your food. Still, sometimes they can overheat a certain portion, causing it to explode. To prevent this, spread out your food in your microwave-safe dish, so that it cooks evenly. [18]
    • Also, stir the food halfway through the cook time to distribute the heat evenly.
    • Make sure the food is in a single layer, if possible.
    • In addition, debone meat, and add a spoonful of water to dry dishes.
  2. Microwave cooking makes steam, which helps heat and sterilize the food. It’s best to trap that steam so that your food cooks efficiently, but don’t trap it so much that it expands and explodes. Cover the dish with a loose lid, paper towel, or plastic wrap while it heats. [19]
  3. Food continues to cook even after the microwave stops heating it. During this time, it’s still hot, and could burn you, so let it rest in the microwave for an extra minute or 2 before you retrieve it. [20]
    • Use oven mitts or a paper towel to protect your skin as you take your food out.
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Expert Q&A

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  • Question
    What materials are not microwave safe?
    Raymond Chiu
    House Cleaning Professional
    Raymond Chiu is the owner of Maid Sailors Cleaning Service, offering affordable residential and office cleaning services. Since its founding in 2014 in New York City, Maid Sailors has expanded to several cities, including Boston, Chicago, and Austin. The company has earned a reputation as one of the most reliable and best cleaning services in the industry.
    Raymond Chiu
    House Cleaning Professional
    Expert Answer
    Metal, styrofoam, ceramic, and chinaware with metal trim should never be microwaved. Some plastic materials can be microwaved, but many of them cannot. It's important to read the label on the bowl before putting it in the microwave if you are unsure.
    Thanks! We're glad this was helpful.
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    Yes No
    Not Helpful 9 Helpful 18
  • Question
    Are printed glass bowls safe in microwave?
    Community Answer
    Most glassware is safe to use in the microwave. The exception is glass with metallic paint or glaze or metal rims. If you're not sure about the type of paint or glaze, avoid microwaving that dish. If you don't suspect metallic paint or glaze, you can test perform the microwave test with a glass of water and see if the bowl heats up.
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  • Question
    Can I use my old arcoroc dishes from the 1970's in the microwave?
    Community Answer
    No, because they can get ruined in the microwave.
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      References

      1. ↑ https://www.canr.msu.edu/news/use_only_microwave_safe_containers_when_cooking_and_reheating_foods
      2. ↑ https://food.unl.edu/article/microwave-safety
      3. ↑ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/cooking-microwave-ovens#13
      4. ↑ https://www.chemicalsafetyfacts.org/health-and-safety/is-it-safe-to-microwave-plastic-answering-common-safety-questions-about-plastics-food-packaging/
      5. ↑ Raymond Chiu. House Cleaning Professional. Expert Interview. 15 October 2019.
      6. ↑ https://www.fda.gov/radiation-emitting-products/resources-you-radiation-emitting-products/microwave-ovens#Tips_on_Safe_Microwave_Oven_Operation
      7. ↑ https://food.unl.edu/article/microwave-safety
      8. ↑ Raymond Chiu. House Cleaning Professional. Expert Interview. 15 October 2019.
      9. ↑ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/cooking-microwave-ovens#11
      1. ↑ https://www.chemicalsafetyfacts.org/health-and-safety/is-it-safe-to-microwave-plastic-answering-common-safety-questions-about-plastics-food-packaging/
      2. ↑ https://www.chemicalsafetyfacts.org/health-and-safety/cooking-with-silicones/
      3. ↑ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/cooking-microwave-ovens#11
      4. ↑ https://www.electricalsafetyfirst.org.uk/guidance/product-safety/microwaves/
      5. ↑ https://ceh.org/yourhealth/lead-in-dishes/
      6. ↑ Raymond Chiu. House Cleaning Professional. Expert Interview. 15 October 2019.
      7. ↑ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/cooking-microwave-ovens#11
      8. ↑ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/cooking-microwave-ovens#11
      9. ↑ https://food.unl.edu/article/microwave-safety
      10. ↑ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/cooking-microwave-ovens
      11. ↑ https://food.unl.edu/article/microwave-safety

      About This Article

      Article Summary X

      To test if a dish is microwave-safe, look for a symbol with wavy horizontal lines on the bottom, which indicates the material is heat-safe. If you don't see the stamp but you know your dish is made of ceramic, glass, or china, it can probably be used safely in a microwave. If you want to double-check, put the dish and a cup of water inside the microwave and zap them together on HIGH for 1 minute. If the dish is warm and the water is cold, the dish isn't microwave-safe. To learn about materials that should never be microwaved, read on!

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