I don't know if those are sources, but if you've installed it like this:
then the only thing you have to do to uninstall the software is to do a make uninstall, when you're in the original folder.
So when you've extracted netscape.tar.gz
tar -zxvf netscape.tar.gz
then went in the folder
then configure, make & make install
now in order to undo the make install, do a make uninstall.