Yes. You can use non-abrasive soft clothes or duster to clean the solar panels to remove upper layer dust. Try to do it in an interval of 5-7 days, based on the dust levels to avoid unecessary wearing chances. You can use water for clearning twice a month to remove hard to remove layers of dust with the help of soft-bristle brushes. Keep it mind not to use high pressure water.

To estimate how much electricity your solar system can generate in a day, you need a few key pieces of information:

The total DC capacity of your solar system (in kW)

The average number of peak sunlight hours in your area (also called solar irradiation)

Just multiply your system size by the peak sunlight hours to get the theoretical daily generation.
For example, if you have a 3 kW system and your area gets 5 hours of good sunlight daily, then:

3 kW × 5 hours = 15 units (kWh) per day (theoretical)

However, in real-world conditions, solar systems usually operate at about 78% to 80% efficiency due to energy losses (from wiring, inverter, dust on panels, etc.).

So, you can expect around 20% less generation than the theoretical figure.
Using the example above, the actual generation would be about: