I assume you mean UTF-8, not UTP-8?
It would help if you provide an example of exactly how the problem characters are displayed (boxes, question marks, or simply 'other characters'). That will normally provide a clue as to what the problem is.
It would also help if you explain where you get the problem characters from - are they generated by your code (I assume that would be the case for the euro), or do you get them from somewhere else?
And lastly, do you actually use a backtick, '`', in your email? That would be very unusual...(outside of scripting).