Employees employed ``by'' a country elevator establishment which qualifies for exemption will be exempt, if the ``area of production'' requirement is met, while they are engaged in any of the customary operations of the establishment which is commonly recognized as a country elevator. Included among such employees are those who are engaged in selling the elevator's goods or services, keeping its books, receiving, handling, and loading out grain, grinding and mixing feed or treating seed for farmers, performing ordinary maintenance and repair of the premises and equipment or engaging in any other work of the establishment which is commonly recognized as part of its operations as a country elevator. An employee employed by such an elevator is not restricted to performing his work inside the establishment. He may also engage in his exempt duties away from the elevator. For example, a salesman who visits farmers on their farms to discuss the storage of their grain in the elevator is performing exempt work while on such visits. It is sufficient that an employee employed by an elevator is, while working away from the establishment, doing the exempt work of the elevator. If the establishment is engaged only in activities commonly recognized as those of a country elevator and none of its employees engaged in any other activities, all the employees employed by the country elevator will come within the exemption if no more than five employees are employed in the establishment in such operations and if the ``area of production'' requirement is met.