You don't need a litter box, some people just like to add one to help keep the cage cleaner between cage changes. Like I said since I added the litter pan I can go a week between changes instead of just a couple days. So long as you make liners at least 3 layers thick the pee will absorb into them without a problem. To wash fleece don't use any chemical detergent, I just use a cup of white vinegar in the washer. Make sure you get as much hay and stuff off the liners before putting them in the washer too, hay will kill the washer. I vacuum all the poop and hay off before putting it in the washer. Also when you get new fleece you need to wash it a few times to get the softener chemicals out of it or it wont be absorbent.
As I said litter training is more putting a pan where they already want to pee, if you notice the chin only pees in one spot then it might be worth getting a litter pan, that way you can just vacuum or sweep the poops up daily and change the soiled shavings. If not and you don't mind washing the liners every day or two then it's not worth it.
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