UTF8 Find Replace Tool?

UTF8 Find Replace Tool?

Forum Members, I am coding in XML and using a validator / parser that
chokes when it encounters a UTF8 related text hiding within my text. I am
using NotePad++ in ANSI mode, and when I switch it to UTF8 mode it shows
me where these UTF8 errors exist. Once I manually delete the unwanted UTF8
text character my validator/parser works perfectly.
NotePad++ is not able to find and replace UTF8 characters within an XML
file. My question to anyone out there. Does a NotePad++ plugin exist that
will let me globally search the file for unwanted UTF8 text and replace it
with NOTHING? Also, can a RegEx find and replace unwanted UTF8 text? Is
there a text editor out there that is capable of hunting down unwanted
UTF8 text?
In addition, can anyone out there educate me about UTF8 text and why do
they prevent an XML validator from working correctly? I spent several
hours trying to figure out why my XML code was not successfully parsing
and it would of been a lot easier if I would have had the ability to hunt
down unwanted UTF8 characters. Any help will be greatly appreciated.
Thanks in advance.