$ irb
ruby-1.9.1-p378 > string = "Jürgen Müller"
 => "Jürgen Müller"
ruby-1.9.1-p378 > string.force_encoding("BINARY").encode("UTF-8", :invalid => :replace, :replace => "")
Encoding::UndefinedConversionError: "\xC3" from ASCII-8BIT to UTF-8
        from (irb):2:in `encode'
        from (irb):2
        from /Users/norman/.rvm/rubies/ruby-1.9.1-p378/bin/irb:17:in `<main>'
ruby-1.9.1-p378 >