REPLACE('123123Mughal', '123'); 

--------
Result

'Mughal'

Example

SQL> with t as
  2  (select 'Sir littlefoot|Mughal|King' col
  3  from dual union all
  4  select 'oracle|certified|professional'
  5   from dual
  6   )
  7   select
  8   regexp_replace(regexp_replace(col, '[|]',' '),'([0-9]) ([0-9])','\1|\2')
  9   col
 10   from t
 11  /

COL
---------------------------------------------------------------------------
Sir littlefoot Mughal King
oracle certified professional

SQL> connect sys/manager@arla as sysdba
Connected.
SQL> CREATE OR REPLACE FUNCTION no_spec(p_row VARCHAR2) RETURN VARCHAR2 IS
  2       v_result VARCHAR2(4000) := '';
  3  BEGIN
  4       FOR i IN 1..LENGTH(p_row) LOOP
  5              IF SUBSTR(p_row,i,1) >= 48 AND SUBSTR(p_row,i,1) <= 122 THEN
  6                     v_result := SUBSTR(p_row,i,1);
  7              END IF;
  8       END LOOP;
  9  
 10       return v_result;
 11  
 12  END no_spec;
 13  /

Function created.
-----------

Now use it

SELECT no_spec(my_column) from my_table;

You could just use the TRANSLATE function:

PROCEDURE no_special_chars
IS
  ok_characters VARCHAR2(1000) :=
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz012456789., ';

  -- add to 'ok_characters' all the characters that are ok to keep...any characters NOT in this
  -- list will be removed through the use of the TRANSLATE function.

BEGIN
  UPDATE my_table
     SET column_name = TRANSLATE( column_name, ok_characters, ok_characters);
END;

FUNCTION no_special_chars( p_input VARCHAR2 )
RETURN VARCHAR2
IS
  ok_characters VARCHAR2(1000) :=
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz012456789., ';
  return_string VARCHAR2(4000);

BEGIN
  SELECT TRANSLATE( p_input, ok_characters, ok_characters) INTO return_string FROM dual;
  RETURN ( return_string );
END;  

FUNCTION no_special_chars( p_input VARCHAR2 )
RETURN VARCHAR2
IS
  ok_characters VARCHAR2(1000) :=
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz012456789., ';
  return_string VARCHAR2(4000);

BEGIN
  SELECT TRANSLATE( p_input, TRANSLATE( p_input, ok_characters, ok_characters), ok_characters )
     INTO return_string FROM dual;
  RETURN ( return_string );
END;  

Then you could:

SELECT no_special_chars( your_column) FROM your_table;

DECLARE
   str   VARCHAR2 (4000) := 'dd34g67,8;4,jr[7]9[5=-\],o;0';
   nbr   VARCHAR2 (4000);
   n     VARCHAR2 (1);
BEGIN
   FOR i IN 1 .. LENGTH (str)
   LOOP
      n := SUBSTR (str, i, 1);

      IF n IN ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9')
      THEN
         nbr := nbr || n;
      END IF;
   END LOOP;

   dbms_output.put_line (nbr);
END;
/

And this was my target when i was acomplished this task i don't exactly remember

Try this

Create this function by running this script:
-------
CREATE FUNCTION [DBO].[STRIPNONALPHACHARACTERS](@INPUT VARCHAR(255))
RETURNS VARCHAR(255)
AS
BEGIN
    WHILE PATINDEX('%[^A-Z]%', @INPUT) > 0
        SET @INPUT = STUFF(@INPUT, PATINDEX('%[^A-Z]%', @INPUT), 1, '')
 
    RETURN @INPUT
END

--Check it with these
--Select dbo.StripNonAlphaCharacters('abc1234def5678ghi90jkl')
--Select dbo.StripNonAlphaCharacters('1Smith*45')
---------

Then run this script to create the tables, populate, and test:

---------
IF OBJECT_ID('#table1', 'U') IS NOT NULL
  DROP TABLE #table1
GO

CREATE TABLE dbo.#table1
(
      model char(10) NULL
)
GO


IF OBJECT_ID('dbo.#table12', 'U') IS NOT NULL
  DROP TABLE dbo.#table2
GO

CREATE TABLE dbo.#table2
(
      model char(10) NULL
)
GO

Insert into #table1 (model)
select 'ABC*1234'
union
select ('DEF*1234')
union all
select ('GHI*1234')
union all
select ('JKL*56789')
union all
select ('JKL*56789')
union all
select ('JKL*56789')

Insert into #table2 (model)
select ('ABC')
union all
select ('DEF')
union all
select ('GHI')
union all
select ('JKL')
union all
select ('JKL')
union all
select ('JKL')

--See that it does not match
select *
from #table1 t1, #table2 t2
where t1.model = t2.model

--See that it does match with function
select *
from #table1 t1, #table2 t2
where (dbo.StripNonAlphaCharacters(t1.model)) = t2.model
---------

  1  DECLARE
  2     str   VARCHAR2 (4000) := '"9787-765675765,5645-654545656,5665465-65456456,67446466656';
  3  BEGIN
  4     dbms_output.put_line (regexp_replace(str,'[^[:digit:]]',''));
  5* END;
SQL> /

9787765675765564565454565656654656545645667446466656

PL/SQL procedure successfully completed.