With no office and no paid staff, a Twin Cities nonprofit has managed to collect more than 500,000 mittens and hats for low-income children over the past two decades.

That’s on top of raising $500,000 for other charities.

The humbly named Hats & Mittens marks its 20th anniversary this year, a milestone that tickles founder Rebecca Jorgenson Sundquist, who launched the nonprofit with a business plan scribbled on the back of an envelope.

“I hadn’t thought 20 years out,” laughed Sundquist, of Deephaven. “But I could see early on that the idea had merit, there was a real need, and it was easy to execute.”

“Easy” may be in the eye of the beholder. Sundquist is a professional fundraiser, more accustomed to multimillion capital campaigns than modest hat and mitten contributions.

During its start-up years, the nonprofit relied on word of mouth to find children in need. In the third year, it asked Greater Twin Cities United Way to publicize to their charities.

“That’s when we realized the need was incredible,” she said.

Backed by a cadre of dedicated volunteers and board members, and key business support, Hats & Mittens now delivers winter wear to more than 60 schools, community groups and social service agencies. The groups simply sign up at the nonprofit’s website.

The mittens and hats pour in year-round from individuals, corporate collections, nonprofits, and direct product donations from such businesses as Wear-A-Knit Custom Knitware in Cloquet or Once Upon a Child in St. Louis Park.

This week, for example, Sundquist is picking up boxes from the Ordway theater, which sponsored a hat and mitten collection to accompany its Sound of Music production.

Last week, she was lugging boxes from Lake Area Bank of Stillwater, the Marriot Courtyard Bloomington, and Trinity Lutheran School in Waconia, where third-graders are learning to knit hats for an art class.

The pickups aren’t always necessary. Donors also drop off their goods at Sundquist’s or the homes of other board members.

The mountain of clothing — in every color and fabric imaginable — is ultimately sent to a warehouse donated by Steiner Development of Wayzata. The items are sorted and prepared for delivery.

Deliveries are year-round, not just over the holidays.

“We bring it in, and bring it out,” said Sundquist. “It doesn’t do anyone any good to have it sitting around.”

In addition, Hats & Mittens hosts an annual December fundraiser for a nonprofit that catches its eye.

About $45,000 was raised last month for Minnesota Sinfonia, a nonprofit chamber orchestra best known for bringing classical music training to inner-city schools. Next year, the same thing will happen for Ready, Set, Smile, a nonprofit that offers mobile dental care and education for needy Minneapolis children.

Looking forward, Sundquist wants to create an educational curriculum for families and others to complement the hat and mitten drives “to deepen the discussion about the importance of giving,” she said.

Children exposed to charitable giving and volunteerism in the home are more likely to do the same, studies have shown. Said Sundquist: “It’s a concept children instinctively understand.”