Fill The Pipe

I could use some ideas on how I might seal up a pipe that goes through one of the walls in my house. The previous owner added an external chimney for a wood burning stove. The connection through the wall is some type of clay pipe, and has an inside diameter of 8-11/32", or about 8.340". What I wish to do is seal the inside of that pipe. Just to keep air, moisture, critters, etc. from coming in. The stove is long gone and this chimney won't be used.

I've searched for mechanical expandable...

Fill The Pipe