To Restore Sweetness to Tainted Butter

Cut or break the butter into very small pieces ; or, what is better, force it through a course wire sieve, so as to make it small as possible. Then put it into a churn with a sufficient quantity of new milk to swim it, and churn it well ; then take it out and work it well to free it from the milk, adding a little salt if necessary, and it will hardly be distinguished from entirely new butter.

Another way. To every pound of rancid butter, add a pint of water, into which has been put from twelve to fifteen drops of chloride of lime. Mix till all the particles are in contact with the water ; after letting it stand an hour or two, take it out and wash it in fresh water.

Source: Valuable Receipts, J.M. Prescott