I have a top entry litter box (this one: ) and I'm not looking to change it. It keeps my dog from eating cat poop and gives my cat extra privacy. I've become thoroughly unimpressed with clay litter and I have an incredibly tight budget, so I've been switching slowly to pine pellets. I'm using Feline Pine until she's completely switched to the pellets then I'll be using horse pine pellets from Tractor Supply since they're only $5 for 40 lbs. Sifting boxes are great for pine pellets. Does anyone know of a way to turn a regular litter box into a sifting one?