It’s the season of giving. And, oh my, the things people give.

Consider some of the donations made to Dress for Success Boston, which provides suits and other professional attire to low-income women searching for employment.

Nightgowns. Bathing suits. Tennis shoes. Flip-flops.

“One time we got a blazer covered in gold sequins, which was really kind of cool,’’ said Kimberly Todd, the group’s executive director, “but we couldn’t put anyone in that for a job interview.’’

Struck by the holiday spirit of generosity — as well as a desire to clear out their closets for incoming gifts and lock in year-end charitable tax deductions — many people flood nonprofits at this time of year with items that may be perfectly lovely and in pristine condition, but are useless or burdensome to the groups meant to benefit.

And so the groups sometimes have to say no.

The Women’s Lunch Place, for example, a day shelter on Newbury Street, doesn’t generally accept clothing, except winter wear and ponchos.

Still, “people come and say, ‘Happy holidays’ and leave large trash bags or shopping bags full of donations that we have to sort through,’’ said executive director Elizabeth Keeley. “Some are useful but others are not, and we have limited storage space, so when we get everything all at once it’s overwhelming.’’

For the Women’s Lunch Place, the onslaught starts around Thanksgiving and continues into the New Year, resulting in a 50 percent increase in donations, according to Keeley. At Dress for Success, donations double over the winter holidays, causing a serious storage dilemma for the 1,400-square-foot store, Todd said.

Rosie’s Place, the South End women’s homeless shelter, has learned to cope with the outpouring of coats it receives — and wants — each winter by renting a trailer for storage.

“This is a perennial cycle and you plan for it,’’ said executive director Sue Marsh. “Just like the holidays are when stores get busier, there’s a lot of donation activity around this time of year.’’

Then there is the double-edged sword of clothing drives, in which individuals or businesses put out a wide call for apparel donations. Sometimes, unannounced, they then deliver that massive collection to a nonprofit — which, even if it needs the items, may not be able to handle the quantity.

“Some wonderful volunteers once had a coat drive and brought in 100 coats all at once,’’ Keeley recalled. “It was certainly well-intentioned, but they may not realize they weren’t the only ones with that idea.’’

The Pine Street Inn stopped accepting all but winter clothing about a decade ago because the sorting and cleaning became too time-consuming, said the shelter’s spokeswoman, Barbara Trevisan. Yet general clothing donations occasionally still arrive and once included a box of used underwear, which is “not something we’re going to reuse,’’ Trevisan said, “and we had to get rid of.’’

Many organizations spell out their donation needs on their websites. Dress for Success says it tends to get plenty of smaller-size clothing but badly needs items size 12 and up. Rosie’s Place welcomes gift cards for grocery stores and retail chains such as Target. Women’s Lunch Place has a constant appetite for travel-size toiletries, including toothpaste and deodorant.

Some donors are eager to give, but on their own terms, without regard for what the nonprofit could most use.

“I’ve had companies say, ‘We want to do a suit drive,’ and I’ll tell them, ‘What we really need are shoes and purses,’ and they say, “But I really want to do a suit drive,’’’ Todd recalled. “In that case, what I am to say?’’

Inevitably, nonprofits also end up receiving what can only be categorized as garbage: shoes with worn-out heels, sweaters covered in dog hair and pocked with cigarette holes, ripped and stained clothing just a step above rags.

“I think people imagine that someone who is poor or homeless will be happy to get anything,’’ Keeley said, “but we really try to give our women clothing that not only fits them, but is clean and presentable.’’

When Dress for Success receives items it can’t use — and because its standards are high it generally keeps only 25 to 30 percent of what it receives — it typically gives them to organizations such as the Salvation Army and Morgan Memorial Goodwill Industries. Those groups can handle much larger quantities of donations, and have networks of thrift stores that sell all types of items.

Another local beneficiary of unwanted donations is the Big Sister Association of Greater Boston, which has a fleet of trucks available to pick up clothing from people’s homes. It then sells those clothes to thrift stores for between about 30 and 50 cents a pound, a revenue stream that will earn the organization $350,000 this year, according to chief executive Deb Re.

Yet even these beneficiaries-of-last-resort send some donations straight to the trash.

“If you’re replacing your dishes because you want a new style or pattern,’’ they could make a wonderful charitable contribution, said Goodwill chief executive Joanne Hilferty. “But if your old ones are chipped or broken, then you should throw them away — even if Aunt Tillie gave them to you.’’

Some nonprofits that accept clothing would, ideally, like donations to arrive dry-cleaned and on hangers, and appointments for drop-offs are preferred. Even then, they may not be able to accommodate all charitable gestures.

“It’s so tricky because we need the clothing to survive, so it’s very hard for us to turn people away or to seem ungrateful for what we’re receiving,’’ Todd said. “But there are times we’re literally full — like full-to-the-ceiling full — and we just can’t take more donations.’’

Sacha Pfeiffer can be reached at pfeiffer@globe.com. Follow her on Twitter @SachaPfeiffer.