taken from
www.suffolk.lib.ny.us/librari...r3-4.htm
To Make Bone Compost
One who can scrape together several barrel fulls of old bones on his farm can convert them into valuable fertilizer. In order to do this he must decompose the bones. This may be done in several ways. Perhaps the simplest, most effective and most economical way is as follows.

Place the bones in a wooden tank or hogshead, packing them with unleached wood ashes. Supply enough water to keep both bones and ashes thoroughly moistened, and in several months the bones will be so softened that they may be pulverized by merely shoveling them over and sifting them. With the bones and the ashes both on the farm, the farmer may with this simple method, and with no outlay of money, produce a considerable quantity of the very best fertilizer for some lines of vegetables.

Where one wishes to hasten the process, he can use caustic lime instead of the wood ashes. This method means the outlay of some money, and the caustic lime is not easily obtained in remote places.

A third method is to use caustic potash instead of the ashes. Like the lime, this costs something. If the caustic potash can be dissolved and heated, and poured while hot over the bones, at the rate of one part of potash by weight to four parts of bone, it will decompose the bone so that it will be ready to use in several weeks.

If the farmer has several wagon loads of bone on his farm, the result of an accumulation of a year or more, he may not be able to handle it in wooden vessels. In that case he can dig a trench in compact soil, and put the bones in them in bulk to be treated with the ashes, the caustic lime or the caustic potash. The wood ashes will make nearly as valuable a compost with the bone as either of the other two substances named. The farmer can take time to use the ashes. Knowing when he wishes to use it, he can begin three months before that time to use the ashes method. For example, if he wishes to use a bone compost next May, he can collect the bones from now until next December, and in that month he can begin the ashes method. In April he will have the bones decayed so that he can fine them thoroughly, and in May they will be in proper shape to apply to the soil.