LYNN – The city is poised to assault defaced walls, bridge abutments and other locations with water, baking soda and an industrial-strength air compressor.Mounted on a flatbed pickup truck and built by city workers, the graffiti removal machine can strip paint off concrete without pitting a wall or other flat surface or leaving paint residue. The machine uses compressed air to spray high-powered jets of water mixed with baking soda at graffiti.Public Works mechanic welder David Chiaradonna oversaw the machine?s construction this summer and said a courser mix of baking soda can be used to remove particularly stubborn paint. Graffiti plastered across business exterior walls and underneath bridges off the Lynnway prompted Ward 6 City Councilor Peter Capano in June to call for stepped-up efforts to remove graffiti.Acting Public Works Commissioner Lisa Nerich said summer youth workers and crews provided by Sheriff Frank Cousins have done a good job since the summer?s start removing and painting over graffiti, including a rash of scrawled letters and “tags” that covered a block-long Alley Street wall bordering now-closed Lynn Lumber.?I contacted them right after we had the meeting in June. The park buildings that were tagged have been painted. We?re moving forward,” Nerich said.Reports about graffiti vandalism come from various sources, including calls to the city?s graffiti hotline and reports filed by police officers.?The police are a big asset,” Nerich said.She said workers painted utility boxes near English High School, and at Boston and Franklin streets and Market Street at the Lynnway. Graffiti removal crews also responded to graffiti complaints at the Connery School, a wall next to Union Street businesses, walls at Lawton and Western avenues, and an Ellis Street retaining wall.Capano called the graffiti removal machine “a good asset,” but said commuter rail bridges in West Lynn remain tempting graffiti sites, including the Bennett Street bridge underpass.?It?s loaded with graffiti,” he said.Nerich said sheriff?s crews have about a month?s worth of graffiti removal work to do even as the city plans to dispatch the removal machine to graffiti sites in the next two weeks. She said the machine must be operated by two workers and said Public Works employees will begin responding to graffiti complaints after they finish local road repairs.?That?s a priority with kids going back to school. We?re on a tight schedule,” she said.