Huawei SmartAX MT880 User Manual page 4

In case of long-time operation, temperature of the equipment shell
will go up. This is a normal phenomenon.
Cleaning:
Before cleaning the equipment, turn off the equipment and unplug
the power supply.
Clean the equipment shell with a piece of soft cloth.
It is forbidden to spray liquid onto the equipment, to avoid damage
to the internal circuit.
Keep the power socket clean and dry, to avoid electric shock or
other dangers.