6. Come-Clean Corporation produces a variety of cleaning compounds and solutions for both industrial and household use. While most of its products are processed independently, a few are related, such as the company's Grit 337 and its Sparkle silver polish. Grit 337 is a coarse cleaning powder with many industrial uses. It costs $1.20 a pound to make, and it has a selling price of $7.60 a pound. A small portion of the annual production of Grit 337 is retained in the factory for further processing. It is combined with several other ingredients to form a paste that is marketed as Sparkle silver polish. The silver polish sells for $5.00 per jar This further processing requires one-fourth pound of Grit 337 per jar of silver polish. The additional direct costs involved in the processing of a jar of silver polish are: Other ingredients Direct labor $0.55 .36 Total direct cost $1.91 Overhead costs associated with processing the silver polish are: Variable manufacturing overhead cost Fixed manufacturing overhead cost (per month) 25% of direct labor cost Production supervisor Depreciation of mixing equipment $ 3,000 $ 1,500 The production supervisor has no duties other than to oversee production of the silver polish. The mixino equipment is special-purpose equipment acquired specifically to produce the silver polish. Its resale value is negligible and it does not wear out through use Direct labor is a variable cost at Come-Clean Corporation Advertising costs for the silver polish total $3,000 per month. Variable selling costs associated with the