Are you tired of deleting messages one by one... not a problem now here's a free app for you which find and delete messages according to your given options people with too many messages must install this app its free and very efficient
# Delete message received on specific date
# Delete message from a specific contact
#Delete message with specific words(Signature)
#Delete message of specific length
#Delete repeating message'
#Delete all unread message'
#delete all message'
it is also very user friendly