Found in /usr/lib/perl5/5.14.1/pod/perlfaq7.pod
   How do I clear a package?
       Use this code, provided by Mark-Jason Dominus:

               sub scrub_package {
                       no strict 'refs';
                       my $pack = shift;
                       die "Shouldn't delete main package"
                               if $pack eq "" || $pack eq "main";
                       my $stash = *{$pack . '::'}{HASH};
                       my $name;
                       foreach $name (keys %$stash) {
                               my $fullname = $pack . '::' . $name;
                               # Get rid of everything with that name.
                               undef $$fullname;
                               undef @$fullname;
                               undef %$fullname;
                               undef &$fullname;
                               undef *$fullname;
               }
               }

       Or, if you're using a recent release of Perl, you can just use the
       Symbol::delete_package() function instead.