Best way to solve unwanted uri characters.

[eluser]sophistry[/eluser]
there you go. you answered your own question. nicely done. :-)

btw, there is no special CI validation on URI segments.

that is one of the main things to learn when using CI - don't forget about PHP. CI helps you but there is still the whole entire set of PHP functions available to you at any moment.

good luck and let us know how you do going forward.