SQL> create table test_table(data varchar2(100));

Table created.

SQL> insert into test_table values('Test456ing');

1 row created.

SQL> insert into test_table values('55*^$asdf');

1 row created.

SQL> insert into test_table values('12355');

1 row created.

SQL> select * from test_table;

DATA
------------
Test456ing
55*^$asdf
12355

SQL> create or replace function strip_non_numeric(p_string varchar2)
  2  return varchar2 is
  3  result varchar2(100):='';
  4  begin
  5     select translate(p_string,  6  '0ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz*~!#$%^()_-+=&#124}]{{/?.,><','0')
  7     into result from dual;
  8     return result;
  9  exception when others then return '';
 10* end strip_non_numeric;
SQL> /

Function created.

SQL> select strip_non_numeric(data) from test_table;

STRIP_NON_NUMERIC(DATA)
-----------------------------------------------------
456
55
12355

SQL>select translate(data,'0ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz*~!#$%^()_-+=&#124}]{{/?.,><','0') "Result" from test_table;

Result
-------------------------------------------------
456
55
12355

-S.Rajesh Kannan