To stop Ccleaner removing the cookies, when you start that program up, BEFORE clicking on the button to do the cleanup, look at the lhs - there are a whole load of tick boxes.
If you are using Internet Explorer untick the box for cookies in that group (it's the 2nd one down); if you are using another internet browser then click on the Applications tab at the top and they are all listed on the 2nd page. Once you've unticked the appropriate box for removing cookies then you can run the cleaner and leave the cookies in place i.e. you shouldn't have to log in again.