Or this - doesn't drop users who own a schema

declare @sql nvarchar(max)

set @sql = ''

SELECT @sql = @sql+

'

print ''Dropping '+name+'''

execute master.dbo.sp_revokedbaccess '''+name+'''

'

FROM

sys.database_principals

WHERE type <> 'R'

AND NOT EXISTS

(

SELECT 1

FROM sys.schemas s

WHERE s.principal_id = dp.principal_id

)

ORDER BY name

execute (@sql)

.. yes I know it was a couple of months back but I am using it today.