Liners Good liner under loose bedding?

So right now I'm using the fleece/towel/newspaper combo in a C&C cage for my two piggies. But, I'm moving to an apartment and I think it would be more trouble than it's worth to find a place to shake/hang out the fleece, wash it, etc. so I'm thinking I'm going to switch to Carefree bedding or some sort of shavings that I can just throw away afterwards. Trouble is, I can't come up with a good liner for under the bedding. My pigs will eat newspaper if they can get to it, I know you're not supposed to use plastic, and puppy pads are pretty expensive. Anyone have any other ideas? Cage is a 2x3.