XML Cleansing
When writing XML, all text should be converted to UTF8 if it's not coming from a known source. This blog post provides a ruby function to do the conversion.
Secure UTF-8 Input in Rails - igvita.com
don't trust incoming UTF-8 input in rails
How do I replace accented Latin characters in Ruby? - Stack Overflow
Soapbox
interesting rant about ruby 1.9's encoding support. Most it it resonates strongly with my opinions.
Ruby 1.9 Encodings: A Primer and the Solution for Rails « Katz Got Your Tongue?
Another clear summary of the encoding mess of 1.9. With great power comes great ways to shoot yourself in the foot.
removing illegal bytes for encoding in ruby 1.9+ strings | Bibliographic Wilderness