This link shares how to check on & clean up old history for the Alexa intelligent speaker system.  Sometimes background noise is interpreted by the Echo system as a possible command.  

https://lifehacker.com/how-to-listen-to-and-delete-everything-your-alexa-has-r-1826372696

https://www.theverge.com/2018/5/28/17402154/how-to-see-amazon-echo-alexa-conversation-recording-history-listen

Last week a story circulated the web about Alexa recording the personal conversation of a woman and then sending it to a friend of hers. While that was certainly a unique predicament, it can be good to periodically look at what your own Alexa has picked up.  The Verge pointed out today that you can check on what your Alexa does here by going into the Alexa app. When you find things you’d rather not be in her history, you can also delete them on the spot.

KEY PROTECTION FOR ALL USERS — “A good rule of thumb is to avoid saying “Alexa” in general in your home when you don’t want to interact with the device