To delete an Ideabook and remove collaborators in 2024, go to the Ideabook section on your profile. Select the Ideabook you want to delete, click the settings or three-dot menu, and choose the "Delete" option. To remove collaborators, click on the collaborator list, and select "Remove" next to their name. Make sure to save the changes.

I would like to know how to do this too. It is very cluttered.