Here's how to delete an old cellar or fridge:
On the iPhone App:
From the home page, scroll down to Collection Management, then click Manage Cellars & Fridges
Click into the cellar you would like to delete
In the top right hand corner, hit Delete
On the Web App:
On the home page, scroll down to Collection Management, then click Manage Cellars & Fridges
Hover over the 3 dots of the cellar you would like to delete
Then click the trash icon to delete the cellar