I am getting a nice down mummy sleeping bag for Christmas, and I’m hoping to make it last as long as possible. I do a good amount of camping for climbing trips, and that usually results in being smelly by the end of four days. I’m looking for recommendations for a simple sleeping bag liner, likely just cotton or something similar that adds a layer of separation between me and my nice new bag. I particularly am looking for one that’s machine washable and especially covers/ fills the hood of the mummy bag, because I get very a greasy face and hair and want to keep that off the bag. Any recommendations are appreciated, or if people have alternatives for me of ways to keep the insides of bags clean let me know! Cheers!