Remove duplicates loop through columns

I am looking to get a macro to remove duplicates from individual columns, doing so until it's finished with all the columns. I imagine this would be easy-ish for you Excel wizards!

Example:

A B C
Cat Cat Cat
Dog Cat Bird
Bird Dog Bird

Goes to:

A B C
Cat Cat Cat
Dog Dog Bird
Bird

Any help please? You guys did an amazing job last time, so I figured I'd try my luck again.