Amazon CEO Jeff Bezos tours the facility at the grand opening of the Amazon Spheres, in Seattle, Washington on January 29, 2018. Jason Redmond | Getty

If you own an Amazon Echo — or if you're planning to buy one as a holiday gift — you should know a bit about what sorts of private information it stores about you, and how to delete that info. After all, the topic of Alexa and whether it's always listening may come up during the holiday. A judge recently ordered Amazon to hand over Alexa voice recordings in a murder case, for example, which may lead some people to believe the Echo can always hear what you're saying. That's not true. You could be forgiven for thinking otherwise, given some of the bizarre stories out there. For instance, earlier this year, an Alexa-enabled device recorded a conversation between a husband and wife, then sent it to one of the husband's phone contacts. But Amazon says that's because the device accidentally misheard part of the conversation as its wake word, "Alexa," then misinterpreted other sounds as a series of commands. Even without the mistakes, Amazon does collect some information through Alexa. Here's what it grabs, and how you can delete some of that info.

The speakers are pretty good on the Echo Plus Todd Haselton | CNBC

What Alexa hears and saves

According to Amazon's Alexa terms of use, Amazon collects most of what you speak to Alexa. That includes any interactions with Alexa, the location of the product that Alexa is running on, and your voice instructions. Specifically, Amazon says this: Your messages, communication requests (e.g., "Alexa, call Mom"), and related instructions are "Alexa interactions," as described in the Alexa Terms of Use. Amazon processes and retains your Alexa Interactions and related information in the cloud in order to respond to your requests (e.g., "Send a message to Mom"), to provide additional functionality (e.g., speech to text transcription and vice versa), and to improve our services. Amazon says it saves these recordings in the cloud until you ask to delete them. But when I checked, it had stored conversations back to March 2016, but I had an Echo since September 2015, so it's not perfectly consistent. Either way, you should assume that anything you say to Alexa will be stored by Amazon indefinitely. But, understand: Both Amazon's Alexa privacy FAQ and an Amazon spokesperson says Amazon does not record your conversations all of the time, but only when you speak the wake word "Alexa." In other words, Amazon promises Alexa isn't always listening to you.

How to delete what Alexa knows about you

A list of the recordings I've spoken to Alexa. Todd Haselton | CNBC

We've established that Amazon can learn quite a lot about you from Alexa. By collecting your voice requests, for example, it knows the music you ask Alexa to play, the sports teams you're interested in, who you like to call (if you use Alexa to call people), what you like to order by voice and more. The more frequently you use Alexa, the more Amazon can learn about you. You can listen to and delete this information through the Amazon Alexa app on your iPhone or Android phone. Here's how: Open the Alexa app on your phone.

Tap the menu icon on the top-left corner of the app.

Tap "Settings" at the bottom.'

Tap "Alexa Account" at the top of the page.

Select "History." You'll see a list of all of your interactions with Alexa, just like the picture above. You can tap each one to listen to the recording, or to delete the recording from Amazon's cloud. Unfortunately, if you use Alexa as frequently as I do, the list of recordings is prohibitively long to actually move through and delete each voice request one by one. So, if you want to delete everything at once, do this: Visit Amazon's Device page

Select the menu button to the left of the Echo device you'd like to manage. (The menu button looks like three little dots stacked on top of one another.

Tap "Manage Voice Recordings" You'll see a prompt like this: