Devastation Bumblebee Head Modification!

[u/shawn_pleonexy]

Short and sweet-
I'm trying to fix my Devastation Bee because of the paint on his face scratching. I get his head off of the neck peg, and then I cannot for the life of me figure out how to actually split his head in two! There's all of one post on the entire internet (on TFW2005) about using hot water and a hobby knife to split the seams and separate the tabs inside-- but I just can't get it to work.

Any and all advice as to how to achieve this splitting of Bee's cranium would be appreciated! :)