How do I rat litter train my little monsters?

[She's Batty]

So I put a box in my rats cage to hopefully get them to use that as a litter tray.

I put it in the area they usually poop.
I put older poop pellets in there for them to sniff and hopefully realize "this is where I should go".

I fix it up in the morning then I head to school. I come back and it is either moved across the cage and they are sleeping in it, or it is upside down across the cage with chew marks on it.
They have plenty of chew stuff including other cardboard objects just like the box.

I did this for about a week I think before kinda giving up, was that not enough time?

Do they just not like it? Do I tie it down to the bars of the cage with twisty ties?
Try something else?

I'm open for advice and ideas. Help me out awesome rat owners!
Thanks!

<3 my little monsters.

 

[Makura]

tie it to the cage and include urine into the box if you can. most rodents will urinate if you put them in an empty sink cause its cold u could collet it that way.

 

[Makura]

tie it to the cage and include urine into the box if you can. most rodents will urinate if you put them in an empty sink cause its cold u could collet it that way.