hidden/invisible character XML error

Thanks for your suggestions and the the code from Ian will help in other situations but I found the answer to this after receiving the following error:

An invalid XML character (Unicode: 0x1c)

This led me to this post and the code below:

http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:51172#274704

<cfset newxml = rereplace(oldxml, "[\x00-\x1f]", " ", "All")>

Then by working through all the Unicode control codes.  I eventually found the problem codes as being: x1c, x1d, x0c and I replaced them with this:

fieldReturn = rereplace(fieldReturn, "\x1c", " ", "All");

... etc.

So it is something in the character set "[[:space:]]" but what?

Could be one or more of tab, line-feed or carriage-return, that is, one or more of chr(9), chr(10) or chr(13). Browsers usually ignore them, as they're not HTML mark-up. See for yourself.

<cfset testString= "d
                                shell

                                        d"> 

<cfoutput>#testString#</cfoutput>

<cfset aString= "Something I want to investigate">
<cfoutput>
<cfloop from="1" to="#len(aString)#" index="char">
  #mid(aString,char,1)#=#asc(mid(aString,char,1))#<br>
</cfloop>
</cfoutput>

This will output the code of each character.  See what the code is and work from there.