Looking at your original snippet, you can grab the output of your call to $ua->cookie_jar(...)

my $ua  = LWP::UserAgent->new;
my $jar = $ua->cookie_jar({ 
  file           => $full_path_to_script_dir."/cookies", 
  hide_cookie2   => 1, 
  autosave       => 1, 
  ignore_discard => 1});

#... do surfing....

#edit jar
$jar->clear_temporary_cookies
[download]

If you happen to already have a cookie_jar object or want a non-standard one, you can create a cookie_jar and then add it to your UserAgent. Also, these tips also work for things that subclass LWP::UserAgent, like WWW::Mechanize.

my $jar = MyCookieJar->new({ 
  file => $path_to_cookies, %options
});

# directly at new:
my $ua  = LWP::UserAgent->new( cookie_jar => $jar);

# or later, via cookie_jar
$ua->cookie_jar( $jar );
[download]