Kimberly-Clark Corp., newly merged with Scott Paper Co., said it will sell up to 12 mills and eliminate about 6,000 jobs, about 10% of the combined workforce. Wayne R. Sanders, chairman-CEO, said the integration plan is expected to yield annual cost savings of more than $500 million by 1998. Under an agreement with the U.S. Justice Department, the company has plans to divest the Scotties facial tissue business. The company will maintain the Kleenex brand as a full line of premium tissue products and the Scott brand as a full line of value products. The premium brands of Viva and Job Squad towels and Cottonelle bathroom tissue will become sub-brands under the Kleenex name.