It's unclear whether the scavengers are modern-day Robin Hoods or intentionally swiping the goods for themselves.
But charities that solicit these recyclables as donations say the takers are "thieves" cheating Utah's most vulnerable residents.
"It is very difficult to raise money for this population," said ARC of Utah director Doug Hathaway, referring to the 55,000 mentally retarded children and adults statewide who are helped by his organization. "The last thing we need are thieves running around impersonating us."
The ARC of Utah, primarily a disabled-rights lobbying group, got into the secondhand business to fund programs to help its clients become self-sufficient. In doing so, the nonprofit joined a growing number of charities competing for your leftovers.
Groups such as Big Brothers and Big Sisters of Utah and the Multiple Sclerosis Society actively campaign for used household goods, which they turn around and sell by the pound to thrift shops. It's not a lucrative business. Charities pocket only 10 to 20 cents of every dollar that shops pay them.
"We're not wasting money, it just costs us a lot to solicit and deliver the items. That's why it's such a setback for us when they're stolen," said Hathaway.
Last year, the ARC of Utah grossed about half a million dollars from the Salvation Army Thrift Store for throwaway items, but netted only $50,000.
Most of the rest was spent on salaries and health benefits for a dozen phone solicitors, six truck drivers and a supervisor. Rising gas prices also take a toll, as do monthly lease payments on the trucks, said Hathaway.
Other charities report slightly higher returns.
The clothing donation arm of Utah's Multiple Sclerosis Society yields 25 cents on the dollar, or $250,000 for the $1 million in goods it sells each year to the discount store Savers.
A similar outfit working to raise money for Big Brothers and Big Sisters of Utah yields about 15 cents on the dollar, and also sells about $1 million in goods annually to Savers.
These numbers don't look great for charities, which are closely scrutinized for how well they spend donor money. Top rated charities, as reported by the American Institute of Philanthropy, spend no more than $25 to raise $100.
For this reason and other liabilities, charities often shield themselves by creating separate nonprofits to manage their clothing donations. Any money earned is recorded on tax statements of the parent organization as a transfer of income.
Though not the most transparent way to transact business, charities argue the raw numbers don't fairly reflect the value of clothing donations.
In addition to saving landfill space, charity recycling efforts wring far more value from an old T-shirt than you could if you delivered it to a second-hand store yourself, said Jill Silver, associate director of Big Brothers and Big Sisters of Utah.
Those benefiting from clothing drives are donors who get tax credits, charities and those they employ and serve and shoppers at second-hand stores, said Silver. "These donations comprise about 17 percent of our overall budget and are by far, our largest single source of income."
That's assuming, of course, that someone doesn't swipe it first.
Eileen Grahmann, 49, had been stockpiling kitchen knickknacks and toys for months, intending to pawn them off on the first bidder, which happened to be a phone solicitor from the ARC of Utah.
Last Wednesday, she placed a kitchen cabinet and dozens of smaller items on the driveway to her Sandy home, waiting for pickup by ARC drivers the following day. She covered the pile with a tarp.
That same evening, four men in an unmarked red truck pulled into her driveway and scooped up the valuables.
"Two of them looked like they were in their 60s or 70s," says Grahmann, who "thought nothing of it" until she phoned the ARC on Thursday for a receipt and learned their drivers were still en route.
Grahmann never reported the incident to police, saying, "I figure it was my fault. I should have been less trusting."
Police say homeowners are their own best defense against such heists.
Sandy police Sgt. Bill O'Neal suggests people avoid placing valuables on the curb, where they legally enter the public domain and are fair game.
Even Dumpster-diving can be illegal, but only if the trash can is on private property, said O'Neal. "So put stuff in your driveway or doorstep and place a sign nearby, or set up a time to have it picked up while you're home."
Hathaway says donors should be aware that all ARC of Utah delivery people will wear shirts and drive trucks bearing the ARC logo. In addition, all pickups are scheduled, and homeowners will be notified of any changes in the time or date by phone or mail.