Boston, MA 11/16/11 First-graders are eager to use the soap mixture to clean their desks after having lunch. Clockwise from left are: Jennifer Frias (cq), 6, Amy Nguyen (cq), 6, and Poker Meas (cq), 6. Barney J. Brawer (cq), principal of the Michael J. Perkins School (cq), talks about the underchosen elementary school in South Boston, that is also a high achiever on the 3rd-grade MCAS. He gives The Boston Globe a tour, on Wednesday, November 16, 2011. (Pat Greenhouse/Globe Staff); Reporter: Vaznis; Section: Metro; Slug: XXX