Generally speaking, I woudl NOT remove the 'log' directories. Occasional useful information is written into the 'debug.log' and the 'inet.log', and, you may also have a 'media.log' file that can be VERY useful, although I don't know if this was true for DP 5.5
That is not to say that you can't delete or rename the files if they are getting too big, and use the 'touch' command to recreate them
From a support standpoint, we usually only need to go back no more than 1 week in the 'debug.log' or the 'inet.log' files, but, they will keep growing on a daily basis