When you say 'currently' does that mean it may be implemented?
I can see why it won't, because the .gid is stored everywhere and a complete scan of an harddrive would take much longer than a run of CCleaner. But with the coming of indexed file systems, this would be a nice addition to CCleaner.
Thanks for the tip about EasyCleaner, but since this is the only thing I'm missing so far I'll live with CCleaner & manual deletion