Dear Recyclebank: Are old house keys recyclable, since they're made of metal? –Annette B.

Dear Annette: Great question. Keys can be reused, donated, or recycled — however, chances are they cannot be recycled curbside, because keys are considered scrap metal. If you are wondering what to do with a growing collection of unused metal keys, you have plenty of fun and interesting options.

Repurpose your old keys

Old keys can be used in new ways that don’t involve a lock:

Zipper pulls: An easy and quick fix for a missing pull-tab.

Jewelry: Start with a key on a simple necklace chain, or get more elaborate.

Boot-treads cleaner: Keep a key near your front door. They’re great for getting stubborn mud off your soles.

Letter opener: Keep one at your desk for going through the mail.

Home décor: Keys can make for unique wall hangings, wind chimes, or chandeliers.

Home improvement: It’s amazing what you can do with a little ingenuity.

Donate your old keys

You can donate your keys to an arts project, an antique store, or to a charity. Old keys are being used for good by organizations that serve the homeless and by schools to help low-income families. Keys For Hope, and Keys For Kids are two charitable foundations that will put your old keys to good use.

Recycle your old keys

Plain-metal house keys, and the like, are considered scrap metal. Many cities do not offer curbside pickup for scrap metal, so be sure to store your unwanted keys until you are ready to head to a local specialty recycling center. As always, it is a good idea to research the guidelines of what is accepted before making your way to any recycling center. You can help out the recycling process by removing any adhesive or plastic lining from your unwanted keys.

Non-electronic keys that have hard-plastic covering part of the key are most likely not accepted even at specialty recyclers because it’s too difficult to separate the materials.

Electronic keys, such as car keys with a built-in chip, or remote, are generally not accepted at recycling centers because of their electronic components. Take electronic keys to a local e-waste recycling event.

More info

The pure metals from the periodic table of elements (for example, iron, copper, nickel, titanium) are typically too soft, or too brittle for common uses, so metallurgists (metal designers) usually combine one or more metals in certain ratios to form what are known as alloys.

These “metal designers” tweak the ratios and other parts of the recipe to achieve desired performance characteristics of the finished metal. The recipe that leads to the type of metal made, determines how it can be recycled because different materials have different recycling processes.

Millions of keys are thrown away each year. Taking the extra step to recycle, reuse, or donate your old keys helps to reduce waste and keep these cool materials in use.