This Wednesday and next, the Health Department is offering free classes on rat prevention in East Harlem and the Bronx (details). Or, as the Post puts it, it's a "three-hour cram course on keeping the long-tailed terrors from feasting on the fetid buffets inside trash bags." (Think about that as garbage lingers on the streets). Health Department Assistant Commissioner for Pest Control Mario Merlino says, "Rats could chew through everything except plate steel." Oh, and "A quarter-inch hole is all it takes for a full-grown adult rat to penetrate your home or garbage room, Merlino said."