Mayor Bloomberg and his schools chancellor, Joel Klein, will have their hands full implementing the sweeping changes in the school system that they announced this week. But they’d be wise to take some hours out to take on a lingering mess — the $466 million a year that the city’s schools pay for custodial staff, services, hardware, and the like. This spending is largely governed by the city’s agreement with Local 891 of the International Union of Operating Engineers, which represents more than 800 school custodians.

Originally signed in 1995, the agreement was due to expire at the end of 1999. It has since held on, with no current effort to renegotiate. It is a disgrace for the city’s schools.

Under the contract, principals do not have control over the custodial staff that care for their schools. Instead, the custodians are independent managers, hiring their own staff and controlling their own school-maintenance budgets.

There are no real requirements on how clean or shipshape a custodian is required to keep a school. An appendix to the custodians’ collective bargaining agreement with the city contains some guidelines on what sorts of tasks fall into this category, but they are explicitly labeled as suggestions: “This subsections [sic] that follow are all meant to suggest the minimum work … however, these are suggestions only,” the appendix states. Among the “suggestions” are such tasks as “wash and disinfect all toilet seats” and “fill all soap dispenser systems.” According to City Council Member Eva Moskowitz, who has been fighting valiantly to change the system, some principals have had to do these relatively simple tasks themselves. In one case, Ms. Moskowitz said, a principal at an arts school had told her that the custodian refused to fill the soap dispensers because he didn’t like the mess the students made in the restrooms. There was nothing the principal could do, since he did not have control over the custodial staff.

The custodians’ contract abounds with strange provisions. Consider the paint rule. Under this clause, custodians are not allowed to paint a wall above 10 feet. At that mark, the painters’ union is supposed to be brought in to finish the wall. This arrangement presents a logistical problem, as the painters’ union and the custodians’ union have to be in coordination and, at the least, on speaking terms. According to Ms. Moskowitz, the latter is rarely the case, as the two unions are continually warring. The result, predictably, is a city full of half-painted school walls. Should the wall painting tire custodians and their staff, however, there is some solace. The contract provides for a limit to the amount of “missing floor tiles” they have to replace over the course of a month: 200 in the largest schools, 75 in the smallest. Custodians also do not have to change light bulbs — leaving many principals in the dark, literally, on who is supposed to perform this basic service and with what money.

The contract has served as a basis for abuse. In December 2001 a group of 11 custodians were arrested in a kickback scheme involving contracts that were illegally steered to window washers. Overtime, too, is also easily abused. Custodians are paid overtime for such routine tasks as cleaning up after meals. In addition, whenever a school is without a full-time custodian, a common condition in the current system, a custodian from another school comes in as a “temporary care.” These custodians add 75% to 100% of the salary for a full-time custodian to their regular pay, often for doing nothing more than walking around the school for a half an hour before returning to their regular job.

It would not be entirely accurate to say that principals have no oversight when it comes to the custodial staff in their schools. They give a year-end review of the custodians, and that review becomes the basis for their chances of promotion and any opportunity the custodians might have to earn a bonus on their base salary, which ranges from $58,000 to $92,000, depending on the size of the school they service. A custodian who is acting in a “temporary care” capacity, in addition to servicing a large school, could take home more than $184,000 a year (and more than that if his wife is working for him). A principal, by contrast, makes up to $115,000 a year; Mr. Klein himself makes $245,000.

But the review process comes with a perverse incentive. If a custodian is failing to keep a school sufficiently clean, giving the custodian low marks on the review will only ensure that the custodian stays, since promotions are tied to high marks, and a promotion for a school custodian means moving to a larger school. The system, as it stands, encourages principals to give failing custodians high marks, in order to get them to leave. Call it a social promotion.

When Ms. Moskowitz holds teacher speak-out nights, the biggest topic on the teachers’ minds is lack of paper towels. “Principals need more authority and more responsibility, including over their school’s budgets,” she said. If New York’s schools are to clean up their act, they might want to start with the messy bargain they have made with their custodians.