If you want to remove any unwanted tags it's a quick and easy process.
Go to your Contacts screen and select Delete Tags
Click on the field and a dropdown of all tags will appear
Select the tags you'd like to remove. Click on the box again to add more tags. Once you've selected all tags to remove, click the Delete button
You'll be taken to a screen which will confirm the tags you are deleting and a processing message
Once the process has finished the message will change to complete