Cary Zeschke’s best advertising tools are yellow — but they’re not the local phone books in Bloomington, Ill. The owner of Zeschke Septic Cleaning says he gets the most bang for his marketing buck from his two gleaming vacuum trucks: a 1995 Peterbilt 379 with a 3,600-gallon aluminum tank and a 1996 Kenworth T800 with a 2,800-gallon steel tank.“Those two trucks are traveling billboards,” says Zeschke, whose company’s services center on cleaning septic tanks and grease traps. “Every time I come back from a job, I intentionally drive down the main business streets in Bloomington-Normal, just to display the trucks.“They’re
