Adding Oracle Parameters

Oracle9i Enterprise Edition Release 9.2.0.8.0 - Production
PL/SQL Release 9.2.0.8.0 - Production
CORE      9.2.0.8.0      Production
TNS for 32-bit Windows: Version 9.2.0.8.0 - Production
NLSRTL Version 9.2.0.8.0 - Production

I am trying to add some oracle parameters on my PR3 system and this is what I am getting:
SQL> show parameter spfile;

 NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------

spfile                               string      %ORACLE_HOME%\DATABASE\SPFILE%
                                                          ORACLE_SID%.ORA

SQL>

SQL> alter system set _eliminate_common_subexp =false scope=spfile;
alter system set _eliminate_common_subexp =false scope=spfile

ERROR at line 1:
ORA-00911: invalid character

I believe it does not like the underscore at the start of this parameter _eliminate_common_subexp.   I believe what I need to do is go back to the INIT.ORA type parameter file
SQL> create pfile from spfile;
Manually add all the Oracle Initialization Parameter with underscores (example: _eliminate_common_subexp, _optimizer_join_sel_sanity_check, _optimizer_or_expansion) to the  INIT.ORA  and than create the SPFILE again.

SQL> create spfile from pfile;
Or is there another way of adding these parameters to the SPILE ?
Thanks for your time

I also tried:

SQL> alter system set "_ELIMINATE_COMMON_SUBEXP"= FALSE  scope=spfile sid='*';
alter system set "_ELIMINATE_COMMON_SUBEXP"= FALSE  scope=spfile sid='*'
                 *
ERROR at line 1:
ORA-02065: illegal option for ALTER SYSTEM