Unbelievable, squirrels / rats

[TOMMY47]

Found and blocked the probable hole that was the entryway to the MH.
Used copper scouring pad wedged tightly in hole followed by expanding foam sealant.
Checked it today--copper pushed out and foam chewed up.
Doubled the copper and more foam. See what happens.

[Sez_Hoo_]

Get a cat. I had a mouse once. When it realized a cat lived there, never saw it again.

[TOMMY47]

rexlion-I was just about to google a chew proof sealant.

[rexlion]

Maybe you should fill it with plumber's epoxy putty. Once it hardens, they won't be chewing through it.