While keeping your animal in a crate, to control food, water stains off walls and keep better control of loose hair, purchase clear one side stick roll carpet runners. Moving companies use these runners on steps and walking areas to protect carpets from stains. The runners work like a large roll of scotch tape.
You can adhere carpet roll with the sticky side to the outer sides and rear of the crate.
Just start on one side and roll around to cover the rear and other side and cut with scissors. Once the runner gets overly soiled remove and replace.
One roll will last a long time.
I would not use on puppies/dogs that may try to chew to outside of crate.
What's great is animals can see out, you can better control hair and wall stains and the carpet roll is easy to remove or replace. There is still plenty of air circulation from the front and top of the crates.