Clean up and cash in

Need to make room for a new set of wheels in your garage or new clothes in your closet? Struggling to find shelf space for the toys Santa left for your kids?

Get rid of your old items and you can gain some space and a tax deduction or extra cash. Cars, clothes and toys are among the items you can donate to a qualified 501(c)(3) charity in return for an itemized tax deduction. Or start the new year with a fatter wallet by reselling them online through one of a growing array of sites.

Try these options for donating or reselling everything from books to boats to furniture and appliances.

—By Lucy Maher, special to CNBC.com
Posted 27 Dec. 2014

Clean out your closet and give clothes or shoes to someone who really needs them through one of these organizations:

Goodwill: Money raised through its countrywide network of retail stores goes toward local job training services and education opportunities.

Vietnam Veterans of America: The VVA will pick up your used clothing in 22 states and use the resale funds to aid vets and their families.

Soles4Souls: Find a bin and leave gently worn shoes to be donated to impoverished communities and micro-enterprise organizations for resale.

The Arc: Local chapters of this organization, which helps the developmentally disabled and their families, accept clothing donations.

The Salvation Army: Donate gently worn clothing to benefit the homeless and disadvantaged in your community.

Or sell them for cash or credit:

Tradesy: List your items on this app then accept payment through PayPal. When your items sell, you get a shipping kit in the mail. Tradesy handles returns. Fee: 9 percent of the sale price.

ThredUp: Send in your items; the site determines if your goods are fit for resale or donation. Then you choose between a credit to shop their online store or a payment through PayPal.

Twice: Send your items in a preshipped bag holding 20-30 pieces and get on average $30-$50 for the bag's contents.

Options to donate include:

Habitat Cars for Homes: Donate your car and it could be sold to fund affordable housing for needy families.

American Cancer Society Cars for a Cure: ACS accepts running and nonrunning vehicles with transfer of title and uses the proceeds to fund cancer research, lodging programs for patients who have to travel for treatment and outreach in underserved communities.

National Kidney Foundation Kidney Car: Got a motorcycle collecting dust? The National Kidney Foundation will pick it up and use the proceeds to find research.

If you want to sell it instead, try AutoTrader. Place a $100 ad that stays up until your car sells, or get an instant online offer from a local dealer.

For donating, consider Wheels For Wishes. The Make-A-Wish Foundation accepts and picks up boats then uses the resale funds to grant wishes of sick children ages 2 to 18.

Or rent your boat through Boatbound. This peer-to-peer boat renting program allows you to sell time by the day on your vessel. Think of it as the AirBnB of boats. Boathound takes a 35 percent cut of the rental fee.

One note: If you're planning to donate a large gift like a boat, be sure to look into any additional legalities. "Individuals who are making donations of … highly valued items should contact their attorney, as specific appraisals and additional IRS forms may be required for a tax deduction," said Mollie Cullinane of Cullinane Law Group.

Many hospitals, shelters and police and fire departments accept gently used toys and childrens' clothing. Second Chance Toys—an organization with locations in Washington, D.C., Philadelphia, New Jersey, New York and Boston—accepts gently used plastic toys and distributes them to community groups. Room To Grow, located in Boston and New York, provides essentials for needykids under age 3, and accepts donations such as toys and books as well as towels, bibs, high chairs and strollers.

Or sell the clothes through ThredUp. You'll get medium, flat-rate USPS boxes. Stuff them with kids clothing before sending them back. The box's contents are listed on the site and can be bought by other members for a $5 service fee and $10.95 shipping charge.

If you want to sell your furnishings, try one of these sites:

AptDeco: Those in New York City can post used furniture for sale, paying a 14 to 19 percent selling fee and a delivery charge. The site handles payment transactions and arranges for pickup and delivery.

Lushpad: Owners of used modern furniture can sell their pieces after each is inspected by an internal team. Sellers transact directly with buyers and each ad lasts 30 days.

Furnishly: Got a piece of vintage furniture to unload? Post it on this site and pay a 10-percent commission when it sells.

Options to donate include the Salvation Army, though note that this is not a de facto place to get rid of large pieces no longer in need—the organization will pick up your items, but reserves the right to refuse upon review. Or go through the National Furniture Bank Association. The site lists organizations that accept used furniture and distributes these items to needy families.

Keep in mind that if you're making a donation, it should be itemized and made to an IRS-approved charity, donated by Dec. 31, and deducted at fair market value. "And always ask for a receipt, regardless of the type of gift, amount and organization," said Gina Scott, senior vice president of Pinnacle Financial Partners.

If you donate less than $250, a canceled check or credit card receipt with the name of the charity should suffice. If the gifts are worth $250 or more, the receipt should state that you didn't receive goods or service in exchange, said Scott. (Consult the Salvation Army's Donation Value Guide if you're unsure of the value of your goods.)

If you plan to sell your items, don't forget to check the fee taken by the vendor you're using as well as the return policy in place for buyers.