I needed to disable DV for a OMS upgrade. This recipe applies to 11gR2 on UNIX.
1) Stop Database Control (if applicable), agent (if applicable), listener and database
2) Disable Database Vault:
cd $ORACLE_HOME/rdbms/lib make -f ins_rdbms.mk dv_off ioracle
In 11gR2 one can use chopt to disable DV.
chopt disable dv
3) disable the recycle bin
conn / as sysdba alter system set recyclebin=off scope=spfile; shutdown immediate startup
4) execute dvremov
sqlplus / as sysdba @?/rdbms/admin/dvremov.sql
Done!