SQL & PL/SQL

I have a field to extract from primavera which is in BLOB format in the database and pump it into a view.

we have injected codes to remove the HTML tags such as </> and a few other ASCII stuff ( got the help of a developer on that ACII stuff hence I don't know how to explain pardon me) but we still have surprises like &nbsp and &amp appearing depending on what is entered in primavera.

how do I eliminate ALL html codes? currently the code looks like this:

REPLACE(REPLACE(REGEXP_REPLACE(utl_raw.cast_to_varchar2(dbms_lob.substr(tm.task_memo)), '<[^>]+>'),CHR(13),''),CHR(10),'') AS Narratives

Thank you.