We use yesterday's news. It's quite good but is NOT flushable.
Personally I think flushing litter is a bad idea with any brand. No landlord would be happy with you if you are renting, that's for sure.
We scoop from the litterbox and it goes into a biodegradable dollar store baggy (a box of 60 bags is 1 dollar) and into our garbage. Seems simple enough for us