($CLX) Again spurning the activist investor, Clorox  said Tuesday that Carl Icahn’s latest acquisition offer “substantially undervalues the company and is not credible.” The board’s rejection comes on the heels of Icahn announcing that he would seek to replace the Oakland, Calif.-based company’s directors and buy Clorox for $78 a share if a higher takeover bid didn’t emerge. Icahn had offered to pay $80 a share for Clorox in July.