I just got my fleece about a week ago from an online supplier so i don't know if there is a special type to use, lol. I trust they know what to use. I have an FN and haven't had any problems attaching it. I just lay it in there and it stays in place. My chins pull up the corners every now and again, but that's no big deal. I was worried they may eat it, but they haven't this far. I just wash mine. I washed it on cold and dried it on delicate and it came out just fine. I'm looking into getting a second, possibly a third, liner so it's easier come cleaning time.
My chins love it! I love it! It's soooo much easier to clean the cage now. It's also a lot quieter. My chins and I share my bedroom and I used to hear them jumping onto the base of the cage. It was very loud and sometimes woke me up. With the fleece you can't even hear it!