As the fire would constantly burn, and since there are no chimneys, the ceilings and beams in these homes have now become blackened with soot, particularly the higher in the house they are. The internal bamboo lattice to which the roof thatch would be lashed to would accordingly turn a deep red-brown when polished (called "susutake" 煤竹), and it was sought after by handicraft workers whenever a roof was replaced. One of the main reasons to have such a smokey atmosphere was to help dry out the roof thatch from the inside and extend its lifespan (usually about 25 or 30 years). However the smoke-filled homes did serve an additional purpose, which was to help cure the tobacco leaves that would be hung from the rafters during the winter (until the 1970s, tobacco was the primary cash-crop in the valley. Currently it is no longer grown anywhere in Iya).