You do not want to stick a gas-soaked rag in the neck. That’s Hollywood shit. The risk of it catching in the wrong place or yourself and blowing up in your hand or at your feet is too high.

Plug it with wax or a cork, then tie the soaked rag around the neck, then set on fire and yeet.

Bottle shatters, gas vapour+flame goes poof.

Stay safe, mischief makers.