15 Odd Things You Shouldn't Put in the Dishwasher

©. Leszek Glasner

So. Do you put things in the dishwasher that aren’t dishes? I mean, aside from other kitchenware ... items like baseball hats or Crocs or raw salmon? We wouldn't judge you if you did. In this age of hacks, the dishwasher has become a favorite ally in cleaning all manners of curious objects – and in the case of salmon, of cooking things too. (In case you missed it, dishwasher cuisine is a definite thing.)

In fact, when Consumer Reports asked readers what unusual items they were putting in their dishwashers, the answers were, um, counterintuitive. Like, computer keyboards and car parts. And indeed, a stroll through the endless corridors of the interwebs tells us that we can clean paint brushes, frilly underthings, garden tools, stinky athletic gear, and so much more ... all with a flick of the wash cycle switch.

But is this all such a good idea? While we certainly get weak-kneed for hacks and multitaskers that reduce the number of tools one needs to get a job done, it is equally important to not ask more of an appliance than it is willing to give; likewise, the items being subjected to the dishwasher might not fare so well either.

“The dishwasher is designed to clean dishes, glasses, silverware, pots, and pans. That’s about it,” says Larry Ciufo, the engineer who oversees Consumer Reports’ dishwasher tests.

So while the idea of easily sanitizing something or avoiding the elbow grease required for grime removal might encourage one to toss it all in the dishwasher, we’re here to tell you this: Think about your poor appliance! Not to mention the things you may be subjecting to it. Consumer Reports compiled a good collection of dishwasher no-nos, which we’ve used as a jumping off point for our own list of odd things that don’t belong in the dishwasher.

1. Car Parts

Apparently, this is a popular one. Who knew? (Well, everyone putting car parts in their dishwasher, I suppose.) Ciufo says, “Grease from car parts or machine parts can clog the wash system, and, once clogged, the water can’t circulate to clean dishes. A partial clog allows the water to circulate. But that also means the grease can recirculate through the system, even winding up on your dishes.”

2. Or Any Machine Parts

Same as above, with the additional caveat that adding machine and car parts to the dishwasher can shorten its life as well, according to Joseph Spina from Electrolux, maker of Electrolux and Frigidaire dishwashers.

3. Paintbrushes

And again, same as above – bad for the dishwasher. But also not so great for the paint brushes.

4. Jars With Labels

Since the devil apparently invented the adhesive that sticks labels to jars, some of us (me; do you do it too?) might put the whole shebang in the dishwasher in the hope that the heat and detergent might loosen the gooey glue. Alas, if successful, rogue labels can make their way to the wash system and clog it up.

5. Computer Keyboards

Obviously not good for a keyboard that contains any circuitry, but putting a simple keyboard through the rinse cycle can be problematic too. Aside from water staying trapped inside, if any food particles or detergent residue are retained in the water line, they could end up lodged underneath keys. Don’t turn your QWERTY into QWTY.

6. Certain Plastics

If you use plastic in your kitchen, wash it with care. “A dishwasher’s heat can cause harmful chemicals such as phthalates and BPA to leach from plastics that contain them,” says Don Huber, director of product safety for Consumer Reports. Check the maker’s care instructions and if it is deemed dishwasher-safe, position it in the top rack (away from the hottest part of the machine) and don’t use high wash or high temperature settings.

7. Bras

I had no idea people wash their bras in the dishwasher – however given that a washing machine’s agitator is not kind to lingerie, it makes sense to me. But you obviously shouldn’t put laundry detergent in the dishwashing machine, and dishwasher detergent would generally prove too harsh for delicate fabrics, so there’s that. Also, the heat could be damaging. I vote for handwashing in the sink and line-drying.

8. Cast-Iron Cookware

This may not be that odd, but one of the key rules for cast iron cookware is to encourage the seasoning, not destroy it. The dishwasher will strip that baked-on layer right off, leaving your cookware naked and sticky. See everything you need to know, here: Cast iron pots and pans, demystified.

9. Entire Meals

There are legions of people who like cooking dinner in the dishwasher. While it seems to kind of take the fun out of it for me, who am I to judge? However, manufacturers also rain on this particular parade. LG, for example, doesn’t test its dishwashers for cooking. Taryn Brucia, an LG spokesperson says, “There’s also the question of whether certain foods (like fish and eggs) will be heated well enough in the dishwasher to kill pathogens like Salmonella. Water temperature will not be as consistent in a dishwasher as compared to a stove."

10. Potatoes

Aside from wasting energy and water to do something that can be done effectively in the sink, washing a load of potatoes in the rinse cycle can actually taint them with residual detergent and rinse aid that doesn’t rinse off.

11. Nonstick Cookware

If you’re still using nonstick cookware, be sure to wash it by hand. The wear and tear of the dishwasher can cause the coating to break down, which not only affects the slick finish, but also sets those slippery chemicals free ... and they have lots of problems.

12. Wooden Items

Another classic dishwasher no-no; wooden cutting boards, salad bowls, utensils, etc will all prefer being cleaned in the sink rather than enduring the heat and watery deluge of a dishwasher, which can lead to warping and cracks.

13. Insulated Cups

You’d think containers designed to hold hot liquid would fare well in the dishwasher, but unless your insulated travel mug is marked as dishwasher safe, there can be problems. Namely, the vacuum seal can be damaged, which ruins the whole insulated keep-your-coffee hot part. This also goes for any insulated vessels, like pitchers and tumblers.

14. Printed Measuring Cups

I learned this the hard way. While lab glass and Pyrex may be fierce in the face of the dishwasher, the paint that indicates measurements may not be. You know how valuable a naked measuring cup is? Not very.

15. Antiques and Fine China

You likely already don’t put antique plates and the good crystal in the dishwasher, but since we’re on the topic, we’ll just say it again. Don’t put antique plates and the good crystal in the dishwasher. But people still do it! Remember that the fancy things may be delicate (they weren't designed with dishwashers in mind), and the rattling-about and heat and detergent can all make a mess of grandma's china and crystal.