For knife handles , as long as it is not too "punky" read spongy rotten I would give it multiple applications of thin ca, 24 hrs apart on all sides then finsh with a "Massey" type thinned epoxy for a final coat. Of course this depends on the tang type and intended use. I would not use it on a hidden tang that might be used for heavy chopping or such. For a smaller bladed caper or skinner I would feel quite confidient in it. Just do not breath the ca fumes, darn nasty stuff, cyanide. I have hardened wormy spalted silver maple in this manner for handles and turnery and it has worked great.