I would NOT delete anything with .dat extensions, as those are database files. Other ones should be safe to delete, but back them up first.
Just as a side note, I would be careful not to delete any files from below, as that would affect future jumbo fixes installs (it would most likely not work, as it needs those):
[Expert@GATEWAY:0]# pwd
/opt/CPda/backup
[Expert@GATEWAY:0]# ls
CheckPoint#CPUpdates#All#6.0#5#3#BUNDLE_R81_10_JUMBO_HF_MAIN#78
CheckPoint#CPUpdates#All#6.0#5#3#BUNDLE_R81_10_JUMBO_HF_MAIN#79
DO_NOT_DELETE_FILES_FROM_THIS_FOLDER
[Expert@GATEWAY:0]#