The size of the log and out directories can grow if you do not purge the requests regularly. The sizes you have are large and indicate that it has been a long time since last purge took place.
You should run the request "Purge Concurrent Request and/or Manager Data" and provide a criteria to purge old requests (30 days, for example).
It will take care of the data stored in the database and in the file system.
The files under $AU_TOP/forms are usually several gigabytes in size and should NOT be deleted (unless they are custom forms you developed and no longer needed).