How to clear react native webview cookies?

Solved by using this: https://github.com/react-native-community/react-native-cookies

CookieManager.clearAll();

I used incognito mode as a turnaround and it worked perfect for me.

<WebView
  incognito={true}
  userAgent="Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; AS; rv:11.0) like Gecko"
  source={{
    uri:
      'your url',
  }}
  style={{ flex: 1 }}
/>

At the time I'm posting, CookieManager has poor support for Expo, I had problems clearing cookies after changing a password.

In 2020, for those using Expo, this works:

const RCTNetworking = require('react-native/Libraries/Network/RCTNetworking')
RCTNetworking.clearCookies(() => { })