Deleting Content Types in SharePoint 2010

While developing some content types and site columns for a client, I had the issue of being unable to delete the content types after deleting any libraries and documents that were using them.  The issue turned out to be the second recycle bin that lives at the site collection level.  The process that finally worked is the following:

1. Delete all items using the content type
2. Go to the site level recycle bin (typically accessible from the link toward the bottom of the left navigation bar) and delete items from there.
3. Go to site collection recycle bin (accessible from the Site Collection settings

When these steps were completed, I was able to delete the content types and site columns successfully.