To delete cookies for BLEND website: 

• Open Firefox 
• Copy and paste the following into your browser's address bar: about:preferences#privacy 
• Locate the Cookies and Site Data section and click Manage Data 
• In the Search Websites field, type “blend” and press Enter 
• Click Remove All Shown, then click Save Changes and OK 

To delete all cookies: 

Either open the Cookies window as explained above and use the Remove All Cookies button, or do the following: 

• Open Firefox  
• Copy and paste the following into your browser's address bar: about:preferences#privacy 
• Locate the Cookies and Site Data section and click Clear Data 
• Select Cookies and Site Data and click Clear