my %ship_address;
foreach (@customers) {
    while (@list) {
        my $key = shift @list;
        my $value = shift @list;
        $ship_address{$key} = $value
    }
    # And process...
}

##</code><code>##

my %ship_address;
foreach (@customers) {
    %ship_address = ();
    while (@list) {
        my $key = shift @list;
        my $value = shift @list;
        $ship_address{$key} = $value
    }
    # And process...
}