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Bottom rack of dishwasher loaded with plastic dishware that is still wet.

A Guide to Symbols on the Bottom of Plastic Containers

The stench of burning plastic fills the kitchen, and you know something’s wrong. When you pull the dishwasher door open, steam billows out. Sure enough, a plastic container is warped into a melted mess. Although many of the symbols you find on the bottom of containers appear self-explanatory, it’s remarkably easy to misinterpret one. It may be simple enough to discard a warped dish, but cleaning up melted plastic from the dishwasher is not on anyone’s bucket list. Avoid the hassle by expertly deciphering symbols on containers.  

What Do the Symbols on Plastic Containers Mean?  

Several safety and care symbols on dishware can be interpreted in a handful of ways. This is what they really mean:  

  • Triangle with arrows and a number. The triangle made of arrows refers to recycling, and the different numbers inside that triangle indicate the type of plastic and whether it’s easily recycled or not. 

  • Sometimes, you will also see letters beneath the triangle emphasizing the material.  

  • Cup and fork. This symbol indicates that the material is safe to contact food. Sometimes appearing in a box and sometimes not, the cup and fork symbol is occasionally confused with the dishwasher-safe symbol, which is described next.   

  • Dishes in water. There are several different symbols indicating that a container is dishwasher safe, but the most common is some variation of dishes in water or with water streams or droplets spraying over them. 

  • Box with wavy lines. If the waves are horizontal, the symbol indicates the container is safe to put in the microwave. If the waves are vertical, it’s safe for the oven. Some of these symbols will also note a maximum temperature tolerance. 

  • Snowflakes. When a container has the snowflake symbol, it means it’s safe to freeze. 

  • BPA-free. BPA (bisphenol A) is a man-made chemical sometimes found in food containers and water bottles. A container labelled “BPA-free” does not contain this potentially harmful substance.  

If you frequently recycle or want to, you know that having a system is an essential part of building the habit. To make recycling easier, you may be interested in a pull-out trash and recycling bin built by our reliable friends at Mr. Handyman, who offer carpentry services.  

Different Versions of the Dishwasher-Safe Symbol 

There are various versions of the dishwasher-safe symbol, but not all of them mean the same thing. A box containing plates, or plates with cups, and water lines overhead means the dish should be washed on the top rack only where the heat is less intense. Some of these top-rack symbols also indicate a maximum temperature the material can stand before it starts to melt or warp.  

Symbols that show dishes with water lines or droplets all over the box—not just on top of the dishes—indicate the dish can also be washed in the lower rack. 

Related Topic: Quick Guide to Dishwasher-Safe Water Bottles 

What Happens When You Put the Wrong Container in the Dishwasher?  

It happens. Cleaning up after a long day, it’s easy to throw something that should be hand-washed in the dishwasher and call it good. Unfortunately, the result could be a big mess and ruined dishes. For example, dishes that are not dishwasher-safe can melt, warp, or shatter under the intense heat of the wash or dry cycle. Wooden spoons or cutting boards can warp or splinter. A thermos or nonstick pan could lose the protective coating that makes it insulated or nonstick. All these problems—especially shattered glass and melted plastic—can damage your dishwasher if the mess gets past the filter and damages the drain pump, requiring professional dishwasher repair.  

If your dishwasher is malfunctioning or needs maintenance, you can trust our Mr. Appliance professionals to resolve the issue. Give us a call at (888) 998-2011 or schedule an appointment online.