Do we need to wash the car when returning it ?

I just tidied up the car a little

Only heard filling up gas, never heard of washing the car.

Don't need to wash the car. Need to add enough oil. The gas station has water and brushes to wash the car. Any violations will be deducted from your credit card.

Do not use

Don't need to, because it's cleaner outside due to the rain, but there's mud inside the car. The staff gave us a thumbs up when we returned the car. It's probably because the car is in perfect condition.