Question : how to vaidate xml data within oracle table column

I have loaded data from .csv file(obtained by bcp out from sybase 12.5) into oracle database tables using sqlldr.
I have a column named cust_xml of datatype clob within table customer which has all the xml,speacial character, spanish etc data within it. Some of those xmls are not valid without proper end tag for the sub nodes, unrecognized special characters, spanish characters etc. What is the best way to right away find out which record has invalid xml, special, spanish data.

I tried
SELECT xml_verify(cust_xml) from customer
which is not working saying xml_verify invalid identifier.
Any oracle xml parser etc functions available withing oracle 10g to do it. I am running oracle 10g on my windows OS laptop.
I have many other similar tables with similar xml, special character, spanish data columns.
What kind of special characters, spanish characters oracle does not recognize, support?.
One of the reason I do not see complete XML data within cust_xml column is might be due to unrecognized special characters in between where sqlldr might have skipped that sub node and proceeded to next sub node or record.
Please advise me how can i go about resolving this issues. I basically need to identify the tables with broken xml , special characer etc data and also would like to see best work around to insert entire XML data including all  kinds of special characters, text data, image data some times. Any ideas, links, resources highly appreciated. Thanks in advance.

Answer : how to vaidate xml data within oracle table column

simple way is to convert the clob to XMLTYPE.  If it converts it's at least well formed.

you can do that simply with

select xmltype(cust_xml) from customer where your_id = some_value

you may have to iterate over them in a cursor, capture the exception and report which ones fail.