remove .backup files from pg_xlog

Hello.

I'm running 8.4 and with a backup procedure of
pg_start_backup()
copy base backup
pg_stop_backup()

The backup script failed and the pg_stop_backup command were killed so
now the pg_xlog/ directory has some extra
xxxxxxxxxx.backup files

and in the archive_status/ directory I have the corresponding
xxxxxxxxxx.backup.done files.

So I guess it would be ok to delete the old xxxxxxx.backup and
backup.done files? Saving just the last one, or is there some
unfinished task that pg_stop_backup should have done?
pg_stat_activitity shows no pg_start/stop_backup running