ouch... well, for powder products is the alcohol method: crush the product to dust, and mix it with enough 96% alcohol to make a thick paste. put it back in the pot and let it rest. after 1-2 days all the alcohol is gone and the product is as good as new.
BUT the skinfinish have a different texture, and I'm not sure this will work with them as wel. I suggest you put the remaining in a sifterjar, and use it like that.