Flattened boxes and junk mail, plastic and glass bottles, cardboard and metal cans — into the blue bin they go. While recycling is second nature to most of us, there's likely something else lurking in our closets and basements that also deserves diligent attention when it comes to proper disposal: unused paint.

More than 800 million gallons of paint is sold in the U.S. every year and, according to the EPA, about 10% of that paint is unused. Aside from being a squandered resource, unused paint poured down drains can cause serious damage to pipes and our water system — and, for the record, tossing cans of still-wet paint in the garbage is illegal.

One bright solution: PaintCare, (paintcare.org), a national nonprofit with a robust presence in Minnesota. Steve Pincuspy, Minnesota program manager for PaintCare, tells us more.

Q: What led to the creation of PaintCare?

A: PaintCare was established in 2009 following a dialogue between the paint industry and many government officials, in collaboration with the nonprofit Product Stewardship Institute. The first step was a pilot in Oregon to collect leftover house paints, stains, primers and clear coats. The model worked so well that they wanted to expand it to as many states as possible. Minnesota, under Gov. Mark Dayton, signed a paint product stewardship bill into law in 2013 and we officially launched here in 2014. It's definitely a model our local stakeholders were excited about, and the industry was committed to it.

Q: I'm surprised that only 10 states and the District of Columbia have signed on. Why do you think more states aren't participating in PaintCare?

A: We operate only in states where a paint product stewardship law has been passed. We have to find sponsors and champions in each state to make it work. Minnesota was among the first four or five who adopted the program. There is a nominal fee included that is part of the paint purchase — not a tax and not a deposit! — that supports our mission.

Q: Your company's tagline is "Recycling Made Easy." But I'm guessing most people don't always think about properly disposing of paint or its cousins, stain and varnish. Where might it end up instead?

A: Frankly, many people let it accumulate in their garages and basements — then make it someone else's problem at moving time by leaving old paint behind. One worst-case scenario was a site in St. Louis County, where the sheriff found all these opened cans of paints; someone had poured all the contents into the stream.

Q: Awful. But even pouring paint down the sink is a no-no. Tell us why.

A: Even water-based paint has binders, resins, Latex. It could dry out in the sink and cause clogs or end up in the water treatment system. That would require treating those components to get it out of the system.

Q: What about letting unused paint dry out and only then tossing the can into the trash?

A: It takes a long time for paint to dry out. And liquid paint is considered a contaminant. There are good reasons to not do that.

Q: So, thank you very much — you have made it quite easy for us to do the right thing.

A: Our goal all along has been to make it more easy to recycle. We offer 261 year-round drop-off sites in Minnesota. More than 97% of Minnesotans live within 15 miles of a collection site. About half are paint stores; the rest are locally owned hardware stores. A huge shout-out to Amazon Paint (amazonpaint.com) based in Fridley — no relation to the other Amazon — which recycles Latex paint and is a drop-off location. But all drop-off sites, large and small, appreciate a heads-up, so it's a good idea to call ahead.

Q: How do people find a collection site near them?

A: People can find the nearest collection sites by visiting our drop-off site locator online and putting in their zip code or city and state here: paintcare.org/drop-off-sites/. Anyone with questions, including where to take leftover paint, can contact our hotline during normal business hours at 855-PAINT09 (that's 855-724-6809).

Q: How much paint can we drop off?

A: All sites accept up to 5 gallons per visit, which is about five cans. No aerosols (spray paint), or leaking, unlabeled or empty containers. We also offer a direct pickup service for homes and businesses with 100 gallons of paint or more. We will come to you. Visit our website for the form, and you can schedule a pickup.

Q: How is the returned paint used?

A: Latex goes to Amazon Paints, where roughly half is recycled into like-new paints in 20 stock colors. Some is sent to Oklahoma, where it's turned into alternative daily cover for landfills. Oil paint gets a second life when it's turned into fuel for industrial use. Only a small amount of paint needs to be incinerated or put into landfills.

Q: How successful has the Minnesota initiative been so far?

A: We've collected 7.5 million gallons since 2014. Last year, over 1 million gallons was collected in Minnesota. That's quite a good rate. Minnesota has the highest reuse rate — 9% — in the country.

Q: We might also avoid the need to recycle if we're smarter on the buying end. Any advice?

A: Measure your walls and then work closely with a retailer. They will help you determine how much paint to buy. Try out a color before buying a gallon. And buy just what you need. There's no point in buying a gallon when a quart will suffice.