Easy way to clean up OS X system files Is there an easy way (without completely formatting the disc) to clean all the files in the system folders like bin etc and just leave the needed ones? Different pythons installations like anaconda and playing around with brew or macports left a lot of unneeded files and different versions of different libraries.

Would a repair installation do this?
Macports and Fink are well behaved and put all their stuff in /opt and /sw respectively. Delete those folders and you're done.

Other packages like to use /usr/local, the unix standard for, well, local only installations.

If something is being messy and putting files in */bin, /System, /Library etc. your options are to manually remove things or reinstall the system