Obviously, I have been lucky in the past or they have not been as picky as they seem to be nowadays. The suggestion made by Andreas might be a good solution. In the worst case you will not receive your parcel. Actually, when sending an emptied and perhaps even cleaned stove, there should not be any problem. @Clemens - have you been successful with this strategy?

The small gas burner, which I am using for several years should not pose a risk when added to the checked baggage (stored e.g. in one of the pots) and up to now I never had complaints. I have an adapter for piercing gas cartridges. Those I easily found in all countries I have visited so far. Screw cartridges I could use anyway, but they are more expensive and not necessarily available.