1: Crack the stone open with a hammer. You will see the kernel inside. Note: It is a bit tricky to break the shell without crushing the kernel, so you need to judge the force of the hammer blow carefully.
2: Other way: use a vise in which you could gently break the stone, without damaging the kernel (Thanks to Jean-Paul for the tips).
3: Shell all the kernels like this.
4: Boil a small pan of water and plunge the kernels into it for 1 minute.
5: After this time, drain the kernels in a sieve.
6: Then remove the skins, which should now slip off easily. Your apricot kernels are ready for use...