Clark's sixth and final season with the Bengals was 1978. He played in 14 games and rushed for 187 yards on 40 attempts (a career-high 4.7 average) and caught 11 passes for 43 yards (a 6.6 average). For his six seasons with the Bengals, Clark rushed for 2,978 yards and 25 touchdowns. He also caught 151 passes for 1,139 yards and two touchdowns. Clark was traded to the Houston Oilers prior to the 1979 season, the first of two with the Oilers. In 1979, he rushed for 51 yards on 22 carries (a 2.3 average) and had six receptions for 58 yards. The 1980 season would be his last, when he had just one carry for three yards. He retired prior to the 1981 season. Clark died of a blood clot in his lung at the age of 38 on October 25, 1988 at Memorial Hospital in Jacksonville, Florida. The City of Jacksonville renamed Sherwood Forest Playground as Charles "Boobie" Clark Park and Pool in his honor. In 2000, the Florida Times-Union named Clark number 37 on their list of the top 100 athletes from Jacksonville. In 2001, he was posthumously inducted into the Bethune-Cookman University Athletic Hall of Fame.