Department of Education and teachers union officials could have a deal within weeks that would shrink the number of teachers sitting in rubber rooms.

Sources within the United Federation of Teachers said that the two sides have been negotiating for several weeks outside of contract talks, which have stalled, but would not give any specifics about how the population of teachers in the rooms might be reduced.

The rubber rooms, technically called “reassignment centers,” are student-less classrooms where about 650 teachers and administrators accused of misconduct or incompetence report for duty every day as they wait to be officially charged or have their cases heard. The wait can sometimes stretch over years, during which teachers receive their full salaries. According to Chancellor Joel Klein, last year the city spent some $30 million covering these teachers’ salaries.

Following a New Yorker piece that slammed the UFT for making it extremely difficult to fire rubber room teachers, the rubber rooms and their unhappy inhabitants have become a political problem for the union. But they’ve also become a cost and an irritant to Klein, whose administration has only been able to fire three teachers for incompetence in the last two years.

City and union sources did not disclose how they are planning to drain the rubber rooms. But one relatively easy target could be the rubber room teachers who have been waiting for more than six months for the DOE to wrap up its investigations and charge them with something. Given the expense the city incurs each day these people wait to be charged and the fact that the contract spells out a six month limit for investigations, they could be returned to their classrooms or the investigations could be sped up.

Another cost-cutting item that might be on the table comes from the city’s list of contract demands, which suggest suspending the pay of teachers who have been charged with offenses. Under the plan, a teacher who is later reinstated would be reimbursed at a rate of 150 percent for the pay she missed. The change would not cause rubber rooms to disappear, but it could sharply reduce their ranks. Only teachers who are under investigation and have yet to be charged would remain on payroll and in the rubber rooms.

Klein has argued that the city should not have to pay teachers in rubber rooms “if there is probable cause to believe they are guilty.” Klein has also said that the process of charging and holding termination hearings would be faster if full-time judges decided the cases, rather than the arbitrators who only hear cases a few days a month.

The UFT’s own contract demands call for building up a group of mediators who would try to help the two sides settle cases before they reached a full hearing.

Department of Education officials would not comment on the negotiations.