It should also be pointed out that this keris of Imas is almost certainly
not an mpu made blade and therefore has no yoni to be concerned with. I dare say the the vast majority of keris in our collections also are not mpu made.
I also agree with Henk that immersing the hilt in boiling water subjects the blade to a very similar discomfort that applying a candle flame to it will. Seems 6 of one and half a dozen of another as far as the blade is concerned.