As we approach the holiday season you might find yourself feeling more grateful, compassionate and charitable than at any other time of year. Now is the time when people eagerly donate that load of clothes taking up space in the basement, or employers begin hosting food drives. But is it possible for such a generous act of goodwill to create more harm than good? When it comes to holiday giving, charities sometimes find themselves overwhelmed by volunteer requests and donations. So before you are overtaken by the giving spirit, there are a few things charities and nonprofits are dying for you to know.

No Dirty Clothes?

Tired of looking at those burgundy corduroy pants you haven’t worn since high school? You may be thinking that now is the time to finally give them away to your local charity. Or perhaps you want to donate the broken toy that your kid outgrew. Think again. Charities say that undesirable items are the most frustrating donations to receive. While charities are grateful for the act of kindness, it can put the organization in an awkward position.

“People think they’re doing you a huge favor by giving you dirty furniture or a beat up car,” said Eric Salmi, spokesperson for Catholic Charities. “But the quality of stuff is really important because we’re passing things off to people who we want to feel dignified.”

In some cases, says the Salvation Army, the gift is not only undesirable but not resalable. Jennifer Dean, manager of volunteer engagement at Miriam’s Kitchen, remembers a rather unpleasant experience. She received a donation of clothes so soiled that the case managers were “tied up for an hour picking through them, with masks and gloves on, ultimately having to discard everything.”

Chef John Murphy, also of Miriam’s Kitchen, says it’s common for him to receive half-eaten loaves of bread and jars of peanut butter from college students eager to clear out their minifridges before heading home for holiday break. Staff at Sasha Bruce Youthwork, a shelter for homeless teenagers, say that they tend to receive unfashionable clothes that many young people would not want to wear for fear of getting picked on at school.

People tend to give away items that they don’t want, but charities say it’s best to give a gift that you would use or wear again. Before you think to give away your worst possessions, think about giving your best.

Surprise! Surprise!

You are rushing to your local charity to drop off the boxes of toys your church collected only to find that charity staff members look surprised and flustered. What did you do wrong?

No advance notice.

“It’s wonderful that people are inspired to give this time of year, but without advance notice, we can end up massively overstocked on one item but still very short on several other items that we need,” said Dean of Miriam’s Kitchen.

Calling in advance may also save you a trip. Some groups, such as Catholic Charities, don’t have the storage space to receive an influx of donations and may be forced to crowd their office space with boxes of gifts.

“Just give us a heads up and some time to think about it and figure it all out,” said Salmi of Catholic Charities. He said the group places homeless people in affordable housing so a donation, such as a bed, may need to be routed to the new place of residence. Some groups like Salvation Army can handle surprise drop-offs, but only at designated locations.

Group volunteering can make for the biggest surprise. Perhaps you and your coworkers want to do a team building event by volunteering at a soup kitchen during the holidays. Charities urge these do-gooders to schedule the activity months in advance. Many holiday service opportunities book up well before November. “When volunteers don’t RSVP and just show up, it’s an awkward situation because you don’t want to offend them,” said Michelle Hall-Norvell, communications specialist for Literacy Council of Northern Virginia. Flaking out and missing a volunteer shift can be just as cumbersome for the charity. You might get by with last-minute holiday shopping for your family, but try to plan ahead with charitable giving.

My way or the highway!

You envision the perfect experience that will teach your kids the value of compassion and gratefulness, only to find that soup kitchen opportunities are all booked up. There are opportunities to deliver food to the elderly, but you don’t prefer that. Renee Hoyt-Atkinson of Volunteer Fairfax says it’s important to be flexible. “Be open-minded about what it really means to give,” she said.

That may mean rescheduling for a shift in January or doing something that doesn’t feel as charitable but is a need for a nonprofit. She mentioned an opportunity where kids can make seed balls for a charity that is interested in preserving wildlife.

Flexibility also might mean being inconvenienced. Salmi of Catholic Charities remembers experiences where donors became disgruntled when the charity couldn’t pick up an old car or bed. Salmi hopes donors can occasionally help out by taking the item where it needs to go.

At Sasha Bruce, donors might be surprised to find that the charity wants you to come in to present your gifts personally to the youth. “Anonymous is not always the best way,” said Jim Beck, director of development at the youth homeless shelter. “It’s neat if people want to be part of celebrations. It’s not just good for clients but it’s good for the giver. Instead of just getting the latest iPod, they know the human touch behind it.”

Conversely, there are some nonprofits that cannot accommodate an in-person gift-giving event and only need the gift. Donors may find themselves expecting their perfect idea of charity, but need to be open to doing it a different way or time.

People don’t celebrate my holiday?

When gathering your canned goods and food to take to the food bank, you might tend to focus on collecting canned corn, cranberries and turkey. “People think everyone would love to have Thanksgiving dinner and love cranberries,” said Hoyt-Atkinson of Volunteer Fairfax. “We live in a place where we have a very eclectic population and not everyone eats that food or likes it.”

Some charities encourage people to donate traditional food staples such as canned meat, canned tuna, canned fruit with no sugar added and other foods that are high in protein and low in sugar. She added that healthiness is key. Charities say donors might reconsider giving gifts that are holiday specific, depending on the organization.

But cash is boring

Writing a check or clicking a “donate now” button may not generate the same warm fuzzies as watching an impoverished child open your gift, but don’t underestimate the value of giving straight cash. As charity groups recover from a recession that saw donations dive and demand for services rise, many groups rely on year-end gifts and other financial help to operate. For this reason, the United Way created the “Give Where You Live” holiday giving campaign where businesses can give cash to charities rather than organize a workplace food or clothing drive.

“Nonprofits love cash,” said Beck of Sasha Bruce. “It’s not the sexiest sell for a nonprofit but giving cash gives us the ability to spend the money according to our strategic plan.”

While there are debates in philanthropy about whether donors should support overhead costs or only give restricted funds to a specific project, most charities say that along with in-kind donations, donors should not underestimate the value of cash donations. Giving cash toward international disasters, charities say, is often preferred over donating goods because it’s less costly.

Paul Hebblethwaite, development director of the local Salvation Army, said the group had to turn away many in-kind donations after the typhoon in the Philippines. “It’s cheaper to purchase supplies from the community of a nearby country than to ship the goods,” Hebblethwaite said.

A gift just for you!

You have a desirable donation of the latest electronics that any charity would covet. But before dropping it off, check the needs and the mission of the organization you have in mind. Your sought-after gifts may not be relevant for some charities.

Take Literacy Council of Northern Virginia, for example. The group offers literacy training for nearly 2,000 adults. Hall-Norvell, a communications specialist there, says the staff spends a lot of time recycling donated children’s books that may be insulting for some adults to receive.

Karen Jupiter, development director at Good Shepherd Housing, recalls receiving broken toys and a Halloween pumpkin-head candy bowl for a homeless client who was moving into an apartment. “That’s not the top priority when you’ve been homeless,” said Jupiter.

Every nonprofit has a different mission. Understanding the needs, which may be listed on a charity’s Web site, are of utmost importance.

Don’t be silly, people are only hungry on Thanksgiving!

Quite possibly the greatest holiday giving pang for a charity is that a surge in giving happens only once each year. While many charities depend on the generosity of Americans this time of year, charities hope people can have a plan for giving all year long.

“We are incredibly blessed to have an abundance of volunteers, but people are hungry and need jobs all year long,” said Michael Curtin, chief executive of DC Central Kitchen.

Businesses and individuals might rethink a one-time holiday service blitz. Betsy Cavendish, president of the Appleseed Foundation, said her organization—a public interest justice center—works best when volunteers commit throughout the year. “Our projects are more long-term so we might prefer 100 hours from one person than 100 people giving one hour,” she said.

Charities suggest doing a food drive in June, organizing a Christmas in April event or arranging regular or estate financial gifts. “Charitable giving defines this country,” said Hebblethwaite of Salvation Army. “Whatever amount they give, that’s part of what it means to be American.”