//清除cookiesNSHTTPCookie *cookie;NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];for (cookie in [storage cookies]) {    [storage deleteCookie:cookie];}

 

UIWebView清除缓存：

//清除UIWebView的缓存[[NSURLCachesharedURLCache] removeAllCachedResponses];