PERMATANG PAUH: With four days left to polling, Barisan Nasional has detected dirty tactics deployed by unscrupulous quarters to discredit their campaigning.State BN deputy chairman Datuk Seri Zainal Abidin Osman said pamphlets and brochures were being handed out to voters, attacking the opposition."We want to stress that this has got nothing to do with BN or even Umno."Such campaigning tactics are disgusting."We have stressed from the beginning that our campaigning…