delete large data from a large table oracle

I have a table with 400 million records, with one clob column. Size of table is around 30 gb.

I want to delete 250 million records from it.

I have tried

• traditional delete in small chunks.
• create table as select ...
• insert into select...

All efforts failed, as redo logs were filled, or something happened and session got stuck for over one hour so I killed session.

Any suggestions or method to delete such huge data?

I would do the following:

• CREATED TABLE new_table as select * from old_table where condition
• add indexes on new_table
• add grants on new_table
• add constraints on new_table
• the rest
• DROP TABLE old_table
• rename new_table to old_table