Microwave myths, and what you should never put inside one

Microwaves attract more myths than any other appliance in the kitchen — some harmless, some that cost you an oven. Here are the common ones, sorted into true, false and "it depends", followed by the short list of things that genuinely should not go inside. The theme throughout: the oven is safe and simple when used as designed, and most damage comes from habits, not faults.

Myth: food from a microwave is "radiated" or harmful

False. Microwaves are a form of heating, the same family as radio waves. They make water molecules in the food move and that makes heat. The moment the oven stops, there is nothing left in the food. Food heated in a microwave is simply heated food.

Myth: microwaves cook from the inside out

False, and it matters for safety. Microwaves penetrate a couple of centimetres into the food; the centre heats by ordinary conduction from there. That is why a thick dish comes out hot at the edge and cold in the middle, why the manual says to stir and to allow standing time, and why a turntable that does not turn gives you that cold centre. If the tray is not rotating, seat it properly or book a Turntable Fault (₹350).

Myth: never any metal, ever

Mostly true, with one exception. Foil, spoons, steel bowls, gold-rimmed plates and twist ties arc and can burn the cavity or the waveguide cover. The exception is the metal rack supplied with a grill or convection model, which is designed for grill and combination modes and placed as the manual shows. Use it in plain microwave mode and it sparks. If your oven did not come with a rack, the rule is simply no metal.

Myth: a little sparking is normal

False. Sparking is always a cause: metal, a burnt waveguide cover, a chip in the cavity paint, or running empty. Stop at once, switch off at the socket, and find out which. Caught early it is a ₹350 Sparking Inside visit; left running it can take the magnetron with it.

Myth: running it empty "warms it up"

False and harmful. With no load, the energy goes back into the magnetron. There is nothing to warm up — it is instant. Keep a cup of water in it if you are worried about an accidental start, and use the child lock.

Myth: any plastic is fine if it does not melt

False. Only plastic marked microwave-safe, and not indefinitely — a tub that has warped, stained or gone cloudy has finished its useful life. Thin takeaway tubs and single-use containers are not designed for repeated heating. Melamine plates get very hot and can crack. Glass and ceramic are the easy answer.

Myth: you should not stand near it

Overstated. With the door, glass mesh and seal intact, the oven contains what it produces and stops the instant the door opens. The sensible version of this rule: if the door is bent, the glass cracked, the seal torn or the latch loose, do not use it until it is checked. A Not Starting visit (₹350) covers the door and latch.

Myth: microwaving ruins food's goodness

Not in any way specific to the microwave. Any cooking changes food; shorter heating with less water generally changes it less, not more. Cook as you would cook; the microwave is just the heat source.

Myth: the clock wastes a lot of power

Small. The standby draw is a few watts. The better reason to switch off at the socket in Nellore is not the clock, it is the surge when power returns after a cut, which is what blows fuses. Switch off during cuts and in storms; otherwise leave it.

Myth: it is always cheaper to replace than repair

False for most faults. Turntable, door switch, fuse, waveguide cover, fan — ₹350 on the rate card plus a small part at MRP, and you keep a working oven. The only real replace decision is a magnetron or board on an old oven, or rust through the cavity. Our repair-or-replace guide walks through it.

What should not go in

• Metal of any kind in microwave mode: foil, cutlery, steel tiffins, gold- or silver-rimmed crockery, twist ties, staples, the foil lid on a curd cup.
• Sealed containers: a jar with the lid screwed on, a sealed pouch, a tiffin with the clips shut. Steam builds and the lid can blow off. Loosen or vent lids.
• Eggs in the shell, and whole eggs even out of the shell unless the yolk is pierced. They burst.
• Whole chillies, grapes, tomatoes with the skin on, unpierced potatoes: pierce them. Anything sealed by its own skin steams up.
• Nothing at all: the empty run.
• Water heated for a long time in a smooth cup: it can superheat and erupt when moved. Put a wooden spoon or a non-metallic stirrer in the cup, and do not stare into it as you lift it out.
• Paper with ink or print, recycled paper, brown bags, plastic bags: can scorch or shed.
• Hot oil for deep frying: the microwave cannot control it.
• Baby milk without stirring and testing: it heats unevenly and forms hot spots.

The one rule behind all of them

Put the food in a microwave-safe container with a lid resting on it, not clipped; start it with something inside; stop at the first spark; keep the door and seal in good condition. Do that and the oven will give you years without a reason to call anyone — and when you do call, it will be for a real fault, not a habit.