You could create a job which is scheduled a time X daily or weekly that executes the delete or truncate. A truncate deletes all records from the tables whereas with delete you can be more specific which records to delete.
You might want to consider other users doing requests and updates though.
Second, create a job that will run that stored procedure by the schedule you assigned it.
You creat a job by going to Management forlder in the console. Then click on SQL Server Agents. Then go to Jobs. Rignt click where the jobs would be listed and select new job.
Then it will bring up a new job properties box.
In the General Tab, fill in name and the description.
In the Steps tab, Click on New for a new step. This will open up a Step Properties box. Name the Step. Select the database, and in the command box you will put exec sp_Truncate or whatever yo named your stored procedure. Click ok.
Click on Schedule tab, and select new schedule. This brings up a Schedules property box. The recurring radio box will be marked. Select the Change button, and scheule it the way you want it. It can run monthly, weekly, or daily.