oracle function- modification required

I have a function
CREATE OR REPLACE FUNCTION strip_bad (p_string IN VARCHAR2)
      RETURN VARCHAR2
    IS
       good_string VARCHAR2(62)
          := 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' ||
             'abcdefghijklmnopqrstuvwxyz' ||
             '1234567890';
    BEGIN
      RETURN
       TRANSLATE (p_string, 'T' ||
                              TRANSLATE ( p_string, '.' || good_string
                                                 ,  '.'
                                       ) -- find the bad characters
                         ,  'T');  -- remove the bad characters
  END;
/
This functions removes bad characters.

If the user enters
added more blood bags
its takes off the space and inserts as
addedmorebloodbags.
How can I modify this fucntion to make sure that spaces between words are not removed? Help appreciated.