Because Locksmith adds code to your theme in different places, it's easiest by far to let Locksmith itself remove all of its code on your behalf.
Here are the steps:
- Log in at uselocksmith.com. (If you've previously removed Locksmith from your apps list, you will be prompted to install the app again. This is okay! The installation step is what authorizes Locksmith to make changes to your shop - this is required for the following step.)
- Once you're logged in, click on the "Help" button, then click the red "Remove Locksmith" button.
That's it! If you like, you may head back to the "Apps" section of your Shopify admin, and remove Locksmith from the list.