Each lessee shall remove from the airport or otherwise dispose of in a manner approved by the airport directors all garbage, debris and other waste material (whether solid or liquid) arising out of its occupancy of the premises or out of its operations. Each lessee shall keep and maintain his leased premises in a neat and orderly manner, and shall keep the grass cut and the buildings maintained in a manner approved by the City. The City may require a clean up deposit from any lessee to assure that any premises used by such lessee shall be surrendered to the City in a comparable condition as when the operator received possession, reasonable wear from proper use thereof excepted.