Hot knives are for hash @cannawriter.
You cut hash into small squares. Then you heat 2 butter knives until the blades glow red. (People used the burners on a coil element stove or a torch to get the knives that hot.) Then, you touch a hot knife to a tiny silver of hash and squish it between the 2 knives while you inhale the vapour coming from the smouldering hash.
It’s what people did before dabs. Very popular in the 60s and 70s. ;)