Sometimes, users need to remove items from the Lead Types they've entered into the system. To do so, navigate to Reports ---> Opportunity Report, and filter by Lead Type.
Anything that needs to be "deleted" needs to be reassigned.
Sort by the one you need "deleted", right-click on the job and open in a new tab, edit the Opportunity at the top of the page in the gray box, and type something new into the Lead section. Once all the bad lead types have been reassigned, then it won't appear on the report anymore.
Difference between Lead Types and Lead Source
Lead Type is a broad stroke of where a client came from, and Lead Source is more specific. For example, if you're running multiple radio ads, the lead type would be Radio, and the Lead Source would be the individual radio station. Lead Types can also be reselected, while Lead Sources are typed in every time. Both appear on the Opportunity report and you can filter further to refine your search.