A、By wearing plastic sheets. B、By washing them under a giant pipe. C、By swimming in a nearby swimming pool. D、By taking a shower

Tens of thousands of people from around the world threw tons of overripe tomatoes at each other on Wednesday in an annual food fight that leaves the eastern Spanish town of Bunol covered in red pulp. (30) More than 40 000 people, including many visitors from Australia, Britain and the United States, took part in the tomato fight known as the "Tomatina," now in its 64th year. They were provided with over 100 tons of tomatoes by the town council for the battle which lasted about one hour and left participants covered in pulp and standing ankle-deep in red mush. Many men were shirtless while others wore old clothes, hard hats, goggles or protective plastic sheets. Shopkeepers put up huge plastic covers on their store fronts or boarded them up to protect their properties from the sea of red mush. (31) After a battle, municipal workers and local residents used giant pipes to clear the walls and streets of the tomato pulp in just half an hour while the participants headed to a nearby river where temporary showers were set up. The event cost the town of some 10 000 residents 28 000 Euros to stage, Spanish media reported. The "Tomatina" is held each year in Bunol, located in a fertile region some 25 miles north of the coastal city of Valencia, Spain’s third largest city, on the last Wednesday in August. (32) The origins of the event are unclear although it is thought to have its roots in a food fight among childhood friends in the mid-1940s in the city. It has grown in size as international press coverage brought more and more people to the festival.
30. What can we know about "Tomatina"?
31. How do visitors clean them up after the tomato fight?
32. What is the possible origin of the tomato fight?