[cypher]

You shouldn't even need to clean that much in a cage the size of an alaska, once you know where he's peeing (if you haven't already) put a little tray of chinchilla sand in that spot & he will most likely use that so you can just take out any damp clumps & change the sand every week or even less.
At most I would say clean out about a third of the cage once a month, it depends how much he begins to dig & burrow, if he isn't digging much then you can clean off just the top layer of part of the cage if he does begin to dig a lot then everything falls to the bottom so it's better to do all the fitch in a section of the cage.
They are very clean little things, generally pee in just one spot once settled & you can clean up any areas where dry poo tends to collect but you don't need to worry about that too much.
I usually find it's the area around the wheel that needs cleaning most often, at least the top layer.