Employees engaged in operations which are not an integral part of processing of the named commodities will not come within the exemption. The following activities are not considered exempt under section 13(b)(15):

1. (a) Office and general clerical work.
2. (b) Feeding and housing millhands and visitors (typically this is called the “boarding house”).
3. (c) Hauling raw sugar or molasses away from the mill.
4. (d) Any work outside the grinding season.