sapmnt/SID/global/xxxJOBLG not clearing even after running SAP_REORG_JOBS. What should be done ?

Dear SAPiens,

The sapmnt/SID/global/xxxJOBLG of our Quality box is having 1 million files occupying around 13 GB, since July 2011. We have scheduled SAP_REORG_JOBS with RSBTCDEL and even RSBTCDEL2 with variant sap&001. Technically, shouldn't the job delete all the old files older than 10 days ? We have observed in some forums saying as it should not be directly deleted at OS level.

Now we want the 13 GB space to be cleared. How do we do it in a right way? please advice !!