Why did you change the DB to full recovery in the first place? Full recovery makes log management harder (you need scheduled log backups), not easier.

A DB in simple recovery will not show log backup as the log_reuse_wait_desc, because simple recovery does not need log backups.

Please read through this - Managing Transaction Logs[/url] and this - http://www.sqlservercentral.com/articles/Transaction+Log/72488/