بسم الله الرحمن الرحيم
(Fatwa: 994/1034/L=09/1437)
After you get the cylinder into your possession you will become its owner. Hence it is lawful for you to sell the cylinder in extra amount after taking it into your possession. The extra money shall be halal for you.
Note: If it is forbidden as per the law to do so then you should avoid it.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband
