WebView Switching Pages

In my App with Expo I use the WebView to display some special Websites. To do this, I open the WebView with the URL when a Button is pressed inside the App. This is working perfect. But when I press the Button 1 first, come backe from the WebView and press the Button 2 the Website 1 will be displayed on the WebView for a second or so.

Is there a way to clean the WebView before opening the new Website?

Thanks for your help!