When the masses of visiting American Jews who own vacation homes in Israel's capital leave Jerusalem to return home after Passover, they'll be leaving behind mostly empty apartments - and frustrated Jerusalemites. While many Diaspora Jews consider their Israeli homes an important investment in the Jewish state, many locals say absentee homeowners have driven up market prices, drained the market of available rentals and made many Jerusalem neighborhoods unaffordable for Israelis. That's why a coalition of student activists has launched a campaign to persuade the absentee homeowners to open up their homes to Israeli renters. "We think it's great that foreign Jews are buying here and investing in Jerusalem," said David Uziel, 29, a graduate student in urban planning at Hebrew University. "But if they keep their apartments empty, they are weakening Jerusalem." With many homeowners in Israel for Passover, the students are canvassing Jerusalem neighborhoods with fliers and pressing local real estate agents to offer their clients housekeeping deals: Students will help the homeowners manage their properties, take in the mail and deter thieves in exchange for being able to rent their homes. The Chamber of Real Estate Brokers in Jerusalem, which represents about 200 brokers, has agreed to push the housekeeping option this summer to new buyers from abroad. Benny Lovel, the owner of the Anglo Saxon realty company in Jerusalem, says he will present the option to his foreign clients beginning next month. The phenomenon of absentee ownership in Jerusalem has turned some of its neighborhoods into veritable ghost towns. It also has hurt local businesses that depend on year-round customers. One of five apartments in Jerusalem's central neighborhoods - about 9,200 apartments in total - are foreign-owned, according to a recent review of municipal tax records conducted by an Israeli consulting company. Most of those homeowners are American and French Jews who primarily live abroad but visit Israel for holidays such as Passover and Sukkot, and during the summers. At other times their apartments remain vacant. Many observers say the dearth of affordable housing in central Jerusalem is prompting many Jerusalemites to flee to the suburbs or other cities. Lovel says most foreign homeowners in the city are unaware of these consequences. "Many of them were surprised that they have caused a problem," Lovel said. "They were not aware that the students and Jerusalemites are being pushed out a bit, and they feel a bit apologetic." Though most of his clients do not need the extra cash they could get from renting out their homes, some have expressed an interest in renting as an act out of goodwill, Lovel said. To highlight the problem, a group of some 80 students held a demonstration last December in which the students dressed as ghosts and marched through "ghost town" neighborhoods of Jerusalem, including the upscale David's Village development opposite the Old City's Jaffa Gate. "We walked with megaphones through these neighborhoods shouting, 'Is anyone home?' " said Roy Folkman, the head of Hebrew University's student union. "We saw no one. No one came out." One American homeowner in Jerusalem, who identified himself as Jerry, conceded he used to feel some shame at leaving his Israeli apartment empty most of the year, but now he and his family spend about six months a year in the apartment. "At first I felt a little guilty, but I've been relieved to see that it's become an increasingly common phenomenon that people don't rent out their apartments," he told JTA. "People have very personal furnishings and artwork, and they just don't have the economic necessity to get the income and then run the risk of damage or headache when you rent out to people." Gidi Schmerling, a spokesman for Jerusalem's municipal government, said the city gives scholarships of $100 a month to students who rent apartments downtown. But students say landlords have hiked prices, offsetting the subsidy. Of the absentee homeowners, Schmerling said, "We cannot tell a person who wants to buy a house in Jerusalem how long he can live in the city." Folkman says he hopes the housekeeping rental offer at the least will send Diaspora homeowners a clear message: "You want a living city, you don't want a museum," he said. "And that's what they are making."