Buying new AirPods Pro? Don't throw away your old AirPods, sell them instead.

Noise-cancellation and water resistance make AirPods Pro the best AirPods ever. That means some AirPods owners will upgrade.

The problem? AirPods are notoriously bad for the environment, as hard plastic can take up to 1,000 years to decompose in a landfill. In fact, Apple labels AirPods boxes with a "do not landfill" icon.

And recycling them is incredibly difficult. Recyclers can shred wired headphones and melt them down for copper, but the lithium-ion batteries are glued into AirPods, and pose a high fire risk if shredded. Removing the batteries manually, however, would be cost-prohibitive for recyclers.

Reselling your AirPods for someone else to reuse is clearly the more eco-friendly solution. So why not sell them to help pay for your $249 AirPods Pro instead?

Where to sell your AirPods

More likely than not, your AirPods will die in just a few years because they're powered by lithium-ion batteries that degrade every time you charge them. Retailers know that. As such, not many places will buy your old AirPods from you — not Apple, not Best Buy — but we found a few that will.

1. Amazon

Best value for: Wired first-generation, and cracked or broken AirPods.

Amazon doesn't care which AirPods you have. It will pay you the same price for the first and second generations of AirPods with either the wired or wireless charging case. You'll get $36 for perfect AirPods — those that power on and don't have cracks in them. And for what it's worth, you can still get $9 if they have cracks but power on, or $4.50 if they have cracks and don't power on.

2. 9to5 powered by MyPhonesUnlimited

Best value for: Second-generation AirPods with wired charging case.

9to5, powered by MyPhonesUnlimited, is a little pickier than Amazon, but will pay you just a tad bit more if you have the latest model.

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Regardless of whether you have a wired or wireless charging case, a perfect pair of second-generation AirPods will get you $40 if you give them your charging cord and block. You'll get $30 for the first generation.

AirPods that are "excessively dirty" and have "low volume" will still get you $10, regardless of the model you have. If your AirPods are cracked or completely helpless though, you might have to consider Amazon — 9to5 won't pay you anything for them.

3. BuyBackElectronics

Best value for: Absolutely flawless wireless AirPods.

BuyBackElectronics is the most difficult one to please of the three. Your AirPods won't make the cut if they show signs of heavy use — even if they're fully functional and don't have any chips or cracks.

But if your AirPods are fully functional and free of major blemishes, it'll pay you $27 for a pair with a wired charging case and $37 for a pair with a wireless case. For AirPods that are in absolute mint condition, you'll get $37 for a pair with a wired case and $42 for a pair with a wireless one. If you have a sealed box of AirPods for some reason, BuyBackElectronics will pay you $50 for a pair with a wired case and $60 for a wireless one.

4. Your friends, eBay, etc., and other resale sites

Best value for: All AirPods models, if you're smart about it.

When all else fails, turn to your friends and resale sites. Chances are, someone you know or someone on the internet is willing to pay for cheaper, old AirPods. Make sure you get an idea of how much other people are selling them for. That way you can get the most bang for your buck. Plus, you can keep the profit margin to yourself, rather than helping other resellers make money.

SEE ALSO: AirPods Pro review: Better in every way

Clean 'em before you sell 'em

No one wants crusty, gooey headphones — not resellers, and certainly not your AirPods' next users. So, please, clean out your AirPods before you sell them.

What you need: Lint-free cloth, Q-tip or cotton swab, a toothbrush, and a toothpick or paper clip.

How: Apple advises that you wipe your AirPods and case with a lint-free cloth. Using a Q-tip, pick out any debris stuck to the inside edges of your case. Although Apple also says not to use sharp objects to clean your AirPods, realistically, that's what you'll have to do with tough residue. Brace yourself and use a toothpick or the side of a paper clip to carefully scoop out any earwax that's stuck at the headphone opening. (Proceed with extreme caution though, as you don't want to break the mesh.)

Finally, use a Q-tip or cotton swab to clean the mesh of the headphone opening. A toothbrush will also help clean out the remaining debris.

Warning: Do not use water or solutions when cleaning your AirPods. The first two generations of AirPods are neither water-resistant nor water-proof; exposing them to liquid may cause water damage that'll cause their resell value to plummet.

And viola, that's it. May the odds of selling your AirPods be ever in your favor.