In order to test the fastness of the dyes, untie the skeins and pour boiling water upon them, leave them to soak for about a quarter of an hour, soap and rub them lightly with the hand from end to end and rinse them out thoroughly in as many changes of cold water as may be found necessary, until the water remain perfectly colourless.
Squeeze out all the water you can and let them dry quickly without exposing them to the sun.
Coloured cottons are often washed in vinegar, because it is supposed to affect the colour less than water does.
We have come to the conclusion after several trials that this is a delusion, for the good dyes keep their colour without the aid of vinegar and the bad ones wash out in spite of it.
The fast colours lose none of their beauty in the process nor does it affect the quality of the cotton; any excess of colouring matter which the fibres of the cotton may have absorbed in the process of dyeing is got rid of by this means.
If a piece of work has been done with unwashed cottons and the colours run in the first washing, you have only to rinse it out in several changes of tepid water to restore it to its original freshness and if you want to give it a yellowish tinge, it should be dipped it in weak tea or coffee.