Ho capito come, ho finito per cancellare manualmente ogni cookie per ogni chiave host.
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "locale=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "datr=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "s=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "csm=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "fr=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "lu=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "c_user=");
android.webkit.CookieManager.getInstance().setCookie(".facebook.com", "xs=");
fonte
2014-05-07 14:52:01