If the command
$ scons clean
is run in the base directory all Python byte compiled files *.pyc, all C object files *.o and *.os, and any backup files with the extension *.bak are removed from all sub-directories. In addition any temporary LATEX compilation files are removed from the docs/latex directory.
The more powerful command
$ scons clean_all
will, in addition to all the files removed by the clean target, remove all compiled C shared object files (*.so, *.dylib, *.pyd) and the build and dist directories created when building the Mac OS X application.