I use a small amount of wood pellets in my cages to help soak up pee so that it hopefully doesn't destroy the wood too much. I usually put down some newspaper first, then put a thin layer of wood pellets over the top, then cover them with a thick layer of sawdust so that it doesn't hurt my piggies feet when they walk around! The stuff I use is advertised for use in Cat litter trays, however the ingredients in it and with own testing I can't find anything harmful in it, they don't have particular smell either. Since it's usually buried under the sawdust my pigs don't get to it so they don't eat it. I can't remember the name of it, but I buy it in big 5 litre purple bags from B&M stores.