Hmmm, this delete statement is taking longer than I thought it would...
If you ever have to manually run a SQL delete statement in psql, you can back-up the rows you're about to delete:
\copy ( select * from $table where id in ( ... ) ) to '/tmp/backup.csv'
and, if you've got your filter clause wrong (we've all done it), restore them with:
\copy $table from '/tmp/backup.csv'