Instructions to delete 'traces' on Google Now Picture 1
Step 2: When the new dialog box opens, select Voice & Audio Activity
Instructions to delete 'traces' on Google Now Picture 2
Step 3 : Scroll down to see the entire list searched with Google Now and delete the recordings you want.
Instructions to delete 'traces' on Google Now Picture 3
Above are all steps for you to completely remove "traces" on Google Now, ensuring your privacy.
Having fun!