Say you're no longer using one of your Infura API keys, or one of your API keys accidentally got published on a public code repository; no worries, you can easily delete your existing key and set up a new one.
Deleting an Infura Key
To get started, make sure you're logged in to your Infura Dashboard.
Firstly, in your Infura Dashboard, click the API key you'd like to delete.
Click the 'Settings' tab near the top-right of the page. Then, scroll down to the bottom of the page, and find the 'Delete API Key' button.
Upon clicking that button, a dialog will appear, confirming you to delete the API key. If you've got Two-Factor Authentication set up on your Infura account, you must enter your 2FA code to proceed.
You're all set! If you'd like, you can easily set up a new API Key.