Miele H 7140 BM Operating And Installation Instructions page 14

Warning and safety instructions
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Non-microwave safe plastic dishes can suffer damage or damage the
oven if used with the Microwave  function and or functions that use
microwaves.
Do not use any containers or cutlery made from or containing metal,
aluminium foil, lead crystal glassware, temperature-sensitive plastics,
wooden utensils or cutlery, metal clips or plastic or paper covered wire
ties. Do not use bowls with milled rims, or plastic pots with the foil lid
only partially removed (see "Microwave operation - Suitable containers
for microwave use").
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Plastic dishes that are not suitable for use in an oven will melt and
may ignite at high temperatures and damage the oven.
Use only plastic dishes that are suitable for use in an oven when
using functions that do not use microwave power. Follow the
manufacturer's instructions.
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Fire hazard due to containers made of flammable materials. Plastic
disposable containers must meet the requirements specified for crockery
in "Microwave operation - Suitable containers for microwave use".
Do not leave the oven unattended when heating or cooking food in
disposable containers made of plastic, paper or other inflammable
materials.
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Heat-retaining bags usually contain a thin layer of aluminium foil
that reflects microwave radiation. Because of this, the paper
surrounding the aluminium foil can become so hot that it combusts.
Do not use heat-retaining packaging, such as bags for grilled
chicken, for warming food with functions that use microwave power.
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If the oven is used without food or the food is loaded incorrectly
when using the Microwave  function or functions that use
microwave power, the oven can become damaged.
Do not use any functions that use microwave power to pre-heat
crockery or to dry herbs.
Instead, use the Fan Plus  function.

Preserving and heating food in sealed tins will result in an increase
in pressure, which can cause them to explode. Do not use tins for
preserving or heating food.
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