How to clean log file od a SQL server Database

We are always see that our database file(.mdf) is very low, but the log file is too high nearly 10-100% high or more. One day i saw in our company database, the .mdf file is nearly 500MB but the log file is 35GB. So i tried to clean the log file and got the solution from one of sql server ebooks. So i place that code here to help those people who are having this problem.

Code

USE 
GO
DBCC SHRINKFILE(, )
BACKUP LOG  WITH TRUNCATE_ONLY
DBCC SHRINKFILE(, )

For Example :

USE dbproduct
GO
DBCC SHRINKFILE(dbproduct_log, 10)
BACKUP LOG dbproduct WITH TRUNCATE_ONLY
DBCC SHRINKFILE(dbproduct_log, 10)