Sony ILCE-6600 Help Manual page 566

Hold the camera slightly face downward so that the dust falls out.
Do not subject the product to any shock during cleaning.
When cleaning the image sensor with a blower, do not blow too hard. If you blow the sensor too hard, the inside of the product
may be damaged.
If the dust remains even after you cleaned the product as described, consult the service facility.
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Troubleshooting
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