Do I use response when at a page event (e.g. load) as this is a response from ASP.NET, and request when pressing a button as this is a response going to ASP.NET for processi
The cookies comes from the browser in the Request.Cookies collection. That is where you read the cookies that was sent.
To send cookies back to the browser you put them in the Response.Cookies collection.
If you want to delete a cookie, you have to tell the browser to remove it by sending the cookie with an expiration date that has passed. The browser is using the local time of the client computer so if you are using the server time to create a date, be sure to subtract at least one day to be sure that it has actually passed in the clients local time.