Here are the steps you need to follow to delete an archived board:
Step 1. Go to your Dashboard page and access your archived boards by clicking on “Yes / Show archived/deleted”
Step 2. Now open the archived board you want to delete
Step 3. Click on the clockwork icon (settings)
Step 4. Now choose the “Delete board” option
Final Step. After clicking on the “Delete board” option, you’re going to see a message saying “Are you sure you want to delete the board?”
You need to confirm by clicking on the check button that says “I want to delete this board and all its messages, you can restore this board in the next 30 days.”
Now click on the “Yes, delete it!” button.