在UIWebView下，可以使用

[[NSURLCache sharedURLCache] removeAllCachedResponses];//清除缓存

当使用wkwebview时候WKWebView清除cookies的方法（iOS9以上）

WKWebsiteDataStore *dateStore = [WKWebsiteDataStore defaultDataStore];

  [dateStore fetchDataRecordsOfTypes:[WKWebsiteDataStore allWebsiteDataTypes]

           completionHandler:^(NSArray * __nonnull records) {

             for (WKWebsiteDataRecord *record in records)

             {

//               if ( [record.displayName containsString:@"baidu"]) //取消备注，可以针对某域名清除，否则是全清

//               {

                 [[WKWebsiteDataStore defaultDataStore] removeDataOfTypes:record.dataTypes

                                      forDataRecords:@[record]

                                    completionHandler:^{

                                      NSLog(@"Cookies for %@ deleted successfully",record.displayName);

                                    }];

//               }

             }

           }];

iOS9一下用这种方法：

NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) objectAtIndex:0];

NSString *cookiesFolderPath = [libraryPath stringByAppendingString:@"/Cookies"];

NSError *errors;

[[NSFileManager defaultManager] removeItemAtPath:cookiesFolderPath error:&errors];

查看cookie

NSHTTPCookie *cookie;

NSHTTPCookieStorage *cookieJar = [NSHTTPCookieStorage sharedHTTPCookieStorage];

for (cookie in [cookieJar cookies]) {

  NSLog(@"%@", cookie);

}