How do I clean bronze?

From the 1950s to the 1980s many successful elite weightlifters were from the USSR and parts of eastern Europe, including Bulgaria and Romania. A poll completed by the IWF in 1982 produced Tommy Kono as the greatest weightlifter in history. Tommy Kono represented the United States setting 26 world records, winning 2 Olympic Gold Medals (1952 and 1956) and an Olympic Silver Medal (1960). Kono remains the only weightlifter to set world records in four different weight classes. Vasily Alexeyev of the USSR set 80 world records and won two gold medals during the 1970s. Since then, lifters from China, Iran, Greece and Turkey have competed successfully at the international level. In the history of the sport, only four weightlifters have managed to capture three Olympic gold medals. Naim Suleymanoglu of Turkey won Olympic gold in 1988, 1992 and 1996, while Pyrros Dimas and Kakhi Kakhiashvili of Greece and Halil Mutlu of Turkey repeated the same feat, with three successive victories through the 2000 Olympic Games for the two Greeks, and through the 2004 Games for Mutlu. In 1996, Andrei Chemerkin of Russia won Olympic gold in the Super Heavyweight class. Reports were dominated by photos of the nearly 400 pound weightlifter bounding jubillant and triumphant in mid air over his fully loaded bar, having jumped for joy over his victory. Chemerkin won the bronze in 2000. At the Athens 2004 Summer Olympics, Dimas won a bronze medal in the 85kg class, becoming the fourth weightlifter in history to win a medal at four different Games after Norbert Schemansky (1964), Ronny Weller (2000) and Nikolay Peshalov (2004). The men's Super Heavyweight Class (at present, the 105+ kg category), a perennial favorite among spectators, is currently dominated by Iranian Hossein Reza Zadeh who first set a world record at the world championships and another on the road to a gold medal at the 2000 Summer Olympics. Reza Zadeh has since broken his own records on a number of occasions, including at the 2004 Athens Games, where he captured his second olympic gold medal.