Delete All Keyframes

When you click "Generate Animation" to generate keyframes or actions, you can usually just press CTRL/CMD + Z to undo the keyframes/actions from being generated.

But if that's not available, you can use the "Delete All Keyframes" button in the plugin panel. If you scroll down to the aptly named "Danger Zone" you can find it. Pressing this button will popup a confirmation modal just in case you accidentally press it.

This button deletes all the keyframes or actions from the piano key objects selected in the plugin.

If you need to delete multiple sets of keys, you'll need to use the Auto-Assign Key button to swap between the different sets and delete the keys from each set.