You can use cloth nappies straight from the pack but it's recommended that you wash them first.
All cotton has a 'size' on it to facilitate smooth running through the weaving machines. The size affects absorbency and needs to be washed off.
For best results and maximum absorbency put the nappies through three washes although peak absorbency isn't achieved until around six washes. You don't need any washing powder at this stage and there's no need to dry them in between cycles. When the first cycle stops, leave the nappies in and just start the cycle again.