article background

8 Foods You Should Never Microwave

Don’t microwave these thingsMicrowaves are an essential appliance for many New Zealand households, with 74% of our recent 824 Canstar Blue survey respondents saying that they use their microwave every day. Even so, 7% of respondents admitted to having accidentally destroyed a microwave with something made of metal or by heating something unsuitable. Gen Y were the worst offenders, with 13% having killed a microwave, compared to just 2% of Baby Boomers. Perhaps the microwave technology is just too old-school for our digital natives!

So to help out those less appliance-savvy among us, here is a quick list of some things that you really shouldn’t – ever – microwave.


Well, some eggs are okay to microwave of course – but not if they’re whole, still in their shell. Scrambles, yes. Poached, yes – but hard boiled? No. If you try it, you may just end up with a big, smelly mess to clean up.

Lunch bags

Keep all paper bags and newspapers out of the microwave. Paper and heat aren’t the best of buddies and the two together could cause a fire.

Crockery with a metal rim or decoration

Metal and microwaves don’t mix. We all (should) know that. But sometimes it’s easy to overlook that lovely gold-leaf pattern on your chinaware, or the metal teaspoon that you’ve left in your mug of hot chocolate.

microwave plastic

Is it dangerous to microwave plastic?


Yoghurt containers

If it’s not microwave safe, plastic is another serious no no. This includes things like yoghurt or margarine containers which are likely to melt in the microwave. The same goes for styrofoam containers.

Gel packs

Well, you can put gel packs in the microwave – but if you leave them in too long they’ll spring a leak. A slow, oozy, hot leak.

Travel cups/thermos

If yours is made from stainless steel, don’t even think about closing that door. I know we’re labouring the point, but metal really doesn’t play nice in the microwave. That includes aluminium foil, too.

Grapes on plateFruit

It may seem harmless, but some fruits – including grapes – can’t withstand the heat and are likely to explode. And the chemicals released from hot peppers will sting your eyes when you open the door. Fruit that is mashed, chopped, pureed or I some other way sliced or diced should be fine.


Turn on your microwave with nothing inside to heat and it may well self-destruct. With nothing to absorb the microwaves, the magnetron — the thing that makes the microwave function – ends up absorbing the microwaves and the outcome won’t be pretty. Keep your kids away from the control pad!

Share this article