Ronsonol butane is readily available, it is also flammable just like Protectan, which is/was a mix of butane and propane. A large cylinder of nitrogen, a can of canned air(R134A type), google will find the CAS number for the chemical that is R134A. Then you just look at the ingredients. There is a huge number of posts here on about purging air from bottles. The newer canned air with a stink added might work, it is somewhat flammable as well.