XML : XSLT to remove non-ascii

I need to modify XML document with XSLT. I would like to replace all non-ascii characters by space. Example :

  <input>azerty12€_étè</input>    

Only these caracters are allowed : !"#$%&'()*+,-./0123456789:;=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[]^_`abcdefghijklmno pqrstuvwxyz{|}~

   <input>azerty12 _ t </input>    

I tried to do this in many ways but I have not suceed yet. Thanks for evthg.