Using iMac with OS X Yosemite, Safari 8, cookies reappear when removed in preferences. What needs to be done to stop them reappearing following pressing the remove button?

Most of the sites place multiple cookies.

Delete it twice.

Try this, may help.

Safari > Preferences > Privacy

Additionally, every time you visit a website, it will place another (new) cookie(s). There is no way to permanently disable a site's cookies as some sites will not display their content without allowing them to place a cookie. It's mostly marketing related - they want to know if you've been there before so they can tailor the ads to your preferences. Or, they are used to identify you: I clean out my cookies about once a week or so; if I mistakenly remove a cookie from one of my banks, they will block me and not allow online access to my account because they don't recognize my computer. I have to spend 15 - 30 minutes on the phone before I get a temporary access code. So, be careful what cookies you allow and/or get rid of.

thanks for your input..I had been clearing the unwanted cookies after each session..Even though I had set the preference to always block several always popped in..I finally bought an app called "cookie" which will allow me to identify which sites I will accept cookies from (such as banks) you are right the blanket removal of cookies causes too much grief..thank for your help..