sub prune {
    my $aref = shift;
    @{ $aref } = map {
        if( ref() eq 'ARRAY' ) { ## an arrayref?
            if( @{ $_ ) {  ## Has values, recurse and return the pruned ref (or nothing if it was empty after pruning).
                prune( $_ );
            } 
            else {  ## return nothing
                ();
            }
        }
        else {  ## not an array ref, return it whatever it is
            $_;
        }
    } @{ $aref };
    return @{ $aref } ? $aref : (); ## Still contains something, return it; or nothing.
}

my $refWanted = prune( \@nested );