FYI, the use of “CustomLocation” don’t work for neither of the two elements to be cleaned (I’m under Win 8.1×64 with Ccleaner and Waterfox Classic (installer) last versions !).
Only the cache can be cleaned by including the directory (C:\Users\XXX\AppData\Local\Waterfox\Profiles\xxx.default\cache2\entries\) in custom cleaning of Ccleaner (via the parameters).
No solution therefore for the history which is under C:\Users\JEAN\AppData\Roaming\Waterfox\Profiles\xxx.default