How to delete a content type in SharePoint 2010

This sounds quite simple for lot of people. In order to delete a content type what you need to do is

Go to SiteActions --> SiteSettings --> Galleries --> Site content types  

click on the content type you want to delete, then click on delete this site content type
under settings
.

But this can only be done if the content type is not associated with any list, libraries, etc.

• Say you have a list associated with the content type you want to delete.

In that case you need to go to the relevant list and remove the content type from the list.  

• Say you need to delete the list as well, and you delete the list without removing the content type from the list.

Here's the strange part.

Even though you delete the list,  when you try to delete the content type it gives the error that the content type is still in use.  What happens actually is that the list which was deleted is resides in the recycle bin and content type is still associated with the deleted list. 

In order to solve that problem,

• First  you need to delete the lists from the site recycle bin.

• Then go to the "site collection recycle bin" link at the top description.

• Make sure you delete the content from  "Deleted from end user Recycle Bin" also.

Its done....