Valentino sneakers that retail for $980. A Tovala toaster oven, originally $390. A Clear Home Design Lucite table, which would have cost $899 — except in this case, it was free.

Lena Geller found those items, and many others, in the trash room of her apartment building in Durham, N.C., after scores of Duke University students had moved out at the end of the spring semester.

“It feels wrong for this much stuff to have been thrown out,” Ms. Geller wrote in an article for INDY Week, where she’s a staff writer. She kept a spreadsheet of the roughly 70 items she found in the trash, estimating, after doing some research, that they originally retailed for $6,600 in total.

“I’ve had a few friends text me after reading the piece, like, ‘We should put together some kind of business plan,’” Ms. Geller, 26, said in an interview. “It does feel like most of the stuff that I got was just sitting there. I do think there’s a lot of money to be made.”

Every year, as graduation season ends, many departing students throw away or simply abandon expensive household items and luxury goods instead of donating or taking them back home. Local residents and scavengers are stepping in, rescuing items to reuse or sell, then touting their finds on social media.

Peter Valley, a 47-year-old software company founder, has been selling discarded books from college students for years. To him, and many other scavengers, college campuses are a virtually inexhaustible source of goods that can be resold, kept or donated.