The methods described in the sources involve soaking them in water for at least a month, and then delaminating them or splitting them into two or more leaves using a special knife (c below).
So far the most success I've had with delaminating, aside from carving the layers apart, has been the beef tallow I've been trying on the plates I'm flattening the horn with (since it's been repeated that this is what the plates are supposed to be covered with (Hardwick, P. Discovering Horn, etc.), but I'm not sure that's exactly the "right" or "best" way (and besides at the temperatures I bake the horn at, the tallow starts really smoking...)
Using and working with Horn - Miscellaneous bits. Copyright © 1996,
2001 I. Marc Carlson
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