first skeined pile, which is almost yellow, has to be
bleached. In this region, first of all, pile is washed by
water and soap.
Then it is preserved in 2% to 5% of sodium
hydrosulfite and 1% to 3% formic acid (85) bath, for half
an hour in boiling condition.
bleach it completely, temperature has to be 70 to 80
degree C. After bleaching it is washed very well in hot
water, otherwise the remaining hydrosulfite may destroy
the next dyeing.