CLEVELAND (May 11)—M.A. Hanna Co. plans to sell most of its Cadillac Plastic shapes distribution business to GE Plastics by the end of summer. The sale would trim about $378 million in Hanna sales and focus the company completely on rubber and plastic compounding, colors, additives and resin distribution. The announcement of the sale came three days after Hanna said it would merge with polyvinyl chloride compounder Geon Co. The deal does not include Cadillac´s Richmond Aircraft unit or three Hanna joint ventures in Germany, Spain and France.