The inner bag is made of polyester, not that papery stuff you find in those cheaper dog beds, and it has a zipper closure. Even if you don't have one of our bed covers, you can use our interior bags as a replacement to your current dog bed. 

Insert is fully washable in machine, just safety pin the zipper closed so it doesn't open and release foam during cycle. For the larger sizes, they will fit in a commercial laundry mat washer. You can also put them in the dryer, again, just safety pin the zipper closed. Make sure foam is completely dry before putting cover back on.