?//清除cookies
NSHTTPCookie *cookie;
NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
for (cookie in [storage cookies])
{
[storage deleteCookie:cookie];
}
//清除UIWebView的缓存
[[NSURLCache sharedURLCache] removeAllCachedResponses];?
原文：http://www.cnblogs.com/jz319/p/3796117.html