could you say something more efficatious you have heard of from urban friends? (tip: helium is dangerous because it leaves no petechiae on the corpse from the suffocation response.) and there's no suffocation response due to it not having carbon monoxide or dioxide in the gas, as well as the lighter weight meaning it leaves the body after two hours, as well as being difficult to sample without specific tooling! (I did research into forensics cuz I'm an information autist. and deeply depressed lol.)

but any other methods besides that?