T he holiday season is one of the prime seasons for giving. But there’s a right way to show your charitable spirit—and a wrong way. Here are seven wrong ways:

Dropping off the broken and unfashionable

Charities say undesirable items are the most frustrating donations to receive.

“People think they’re doing you a huge favor by giving you dirty furniture or a beat-up car,” said Eric Salmi, spokesman 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 receiving 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 mini-fridges before heading home for holiday break.

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.

Just stopping by

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.

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.

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 the Literacy Council of Northern Virginia.

My way or the highway!

Had your heart set on working in the soup kitchen only to find the charity wants you to deliver food to the elderly? 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.

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 Youthwork, a youth services group, donors might be surprised to find that the charity wants you to come in to present your gifts personally. “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.”

Conversely, there are some nonprofits that cannot accommodate an in-person gift-giving event and only need the gift.

People don’t celebrate my holiday?

When gathering your canned goods and food to take to the food bank, you might focus on collecting canned corn, cranberries and turkey. “People think everyone would love to have Thanksgiving dinner and loves 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.

Assuming cash is boring

Writing a check or clicking a “donate now” button may not generate the same warmth as watching an impoverished child open your gift, but don’t underestimate the value of giving 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.

Paul Hebblethwaite, development director of the National Capital Area 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.

Forgetting to think before you give

The Literacy Council of Northern Virginia 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 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 can make a real difference.

Only on the holidays

“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.

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.”