I'm just back from a trip to the former Numbami village of Karsimbo for the purpose of getting a breath of fresh air (kisim nupela win) and getting sago starch (paitim saksak). I had a chance to observe the process of producing edible sago from start to finish so I'll attempt a description.
First a suitable tree [Metoxylon sagu] is selected. One near a stream is best so the pulp won't have to be carried far to wash. A man chops down the tree, which is a thorny son of bitch and the kaunsil borrowed my zori [rubber slippers] to do the job. Then the outer bark is removed with an axe or, less effectively, with a bushknife (busnaip). The men usually do such work but women may participate. It's a matter of practicality, not custom. The inner bark is then stripped in slats with the aid of a siala, a large digging stick used also for making holes to plant taro in the garden--a smaller version is stuck in the ground and used to husk coconuts.
The strips of inner bark are then used to catch the pulp. This leaves the pinkish white inner fibery trunk of the tree ready and waiting submissively for you to hammer the crap out of it with a wanginda, a tool with an adze-like handle and a head of anything from a flat, sharp-edged stone to any old shell casing or length of pipe. The handles vary from child- to man-sized thicknesses. Pounding is not limited to one sex or the other and is the most tiring of the chores associated with kundu/saksak/sago palm. Being unskilled immigrant labor my job is mostly pounding which I do rather effectively after my first attempt in which I broke the head (a huge nut of iron) off one wanginda and blistered my hands badly. It requires some skill to combine chopping a piece off the log and smashing the stuff previously chipped off to a fine enough consistency to yield plenty of powder, kundu ano or 'true sago' [or 'sago essence'], when washed. This time I was permitted to do a third of one medium-sized tree and half of a small one (12-14" diam. 10-12' long).
Meanwhile a man constructs a washing machine [or chute] of a section of the outermost covering [of a sago branch] something like a [huge] stick of celery. In the wide mouth of it, he arranges the coconut webbing to filter the fiber out of the powder as he pours water thru it and turns it and squeezes it. The orange colored water runs down the celerylike [stalk] to a hole thru which it drains into a mat of the leathery husk [sheath] of some tree--people in Yap used something similar to sit on when meeting out in the open and theirs was from the areca palm. The coconut tree webbing and the mat, called yáwanji > yáunji, are the only parts of the washing machine to be reused. The hole is plugged with green fiber that both blocks the water from escaping down the rest of the open tube and conducts it down into the mat. [See more images of sago pounding and washing (scroll down).]
The washed pulp (ulasa) is built up around the edges of the mat for support as it gets fuller. When a lot of sago is a-beating several washers are set up. Only men wash and only women (& children) carry the pulp from tree to washer. When all is washed (-lomosa) the powder, kundu ano, will have settled to the bottom in a heavy pasty mass and the water is then drained off (-lapa tina tomu) ['beat water apart'] and the paste scraped off and shaped into large rectanguloid lumps. Green sago fronds are then laid on the ground and the lumps burnt on top of them with dry fronds (damu meaning both 'torch' and 'dry frond' the two being one). The burnt skin of the lumps (baloga) is sweet and considered a treat. The mat is carefully scraped of all the powder, odd bits being dumped in a pan for the dogs. After that the lumps are carried back with the coconut webbing (gogowa--sorry, this is the tube, nuta is the webbing, the laplap (lavalava) bilong kokonas). Bihain [= later] the kaunsil agrees to put the whole thing on tape for me in Binga Numbami; he practiced a bit just now and I could follow most of it fairly well, having seen it all and catching the right cues here and there.