I'm going out with CO from charcoal burning in a small room. This is the only method that I have. I thought about not eating for some time before it and losing as much weight as possible to make it easier and quicker to get high enough CO concentration in the body, would this work?
That's my plan as well. I have a large garage I can do it in. I'm going to use a large tarp to form a tent to make the space smaller. Someone else on this website suggested using a steel bucket to burn the charcoal in. I'm going to drill holes around the outside of the bucket to let air into the bucket to keep the coals burning. I'll have the tent open on only one side, where I'll place the bucket, with a small fan blowing the fumes from over the bucket, into the tent. If all goes well, I think O2 is the most peaceful way to go. Hundreds of people die accidently every year from CO, running their car when stuck in a cold place or a furnace with a clogged chimney and so on. They just pass out and then die.
When I was a teen, a friend in our clique closed up his garage, opened all the windows on his car and turned it on. It worked perfectly. BUT, that happened in the 70s, before catalytic converters became standard on cars. That method won't work with modern cars.