Routinely short of substitutes to fill in for absent teachers, a number of large school systems are appealing to furloughed federal workers to step in and earn some extra cash amid the longest partial government shutdown in the nation’s history.

Metropolitan Nashville Public Schools is among the latest to go on a hiring offensive, urging federal employees on Tuesday to apply to be substitute teachers if they’re looking for work.

“We understand this is a tough time for many families impacted by what is happening at the national level,” said Amber Tyus, director of talent acquisition for the 85,000-student district. “We believe this is a way for workers to find employment that benefits them and the thousands of young people we serve in this district every day.”

Closer to Washington, D.C., several districts in northern Virginia and suburban Maryland are targeting federal workers who are currently without a salary.

Fairfax County Public Schools in Virginia has held two hiring events in the past week, and “the response has been overwhelming,” said John Torre, a district spokesman.

“We are always in need of substitutes,” he added.

Just over half of the 800,000 government workers impacted by the shutdown are deemed “essential,” and therefore must continue to work without pay; the rest have been furloughed.

The nation appeared no closer to a resolution on Tuesday as the shutdown dragged into its fourth week due to President Trump’s funding impasse with Congress. Trump wants $5 billion to build a wall along the U.S.-Mexico border.

Federal workers missed their first paychecks last Friday, and many have struggled to pay their bills and feed their families. But that harsh reality also presented an opportunity for school districts needing professionals who can step into a classroom at a moment’s notice.

In Nashville, a substitute teacher can earn upwards of $1,300 every two weeks. There’s also a big need to support the district’s 5,200-plus certified teachers.

The school system must place substitutes in about 550 classrooms every day as teachers miss school due to illness, vacation, professional development, or other reasons. Tyus says about 900 more people are needed to round out the district’s 1,300-member substitute pool, noting: “We recognize our substitute teachers play an integral part in educating the students of MNPS.”

In Tennessee, substitute teachers must have a high school diploma or their GED, and some districts require a bachelor’s degree.

Applicants in Nashville must complete an online application, submit official college transcripts, clear a background check, and pass an online training course. The paperwork can take less than two weeks to process.

Requirements vary from state to state and district to district, so not all furloughed workers are eligible to work for their local school. For those who are, the American Association of School Personnel Administrators views hiring them as a win-win.

“There is a massive shortage for teachers and substitute teachers, so being creative and making lemonade out of lemons is a fabulous idea,” said Kelly Coash-Johnson, the association’s executive director.

Nationally, teachers miss an average of 11 days a year, according to a 2014 analysis of large districts by the National Council on Teacher Quality.