You do not have to shake the gas cylinder to know the level of its content. Just wet a side of the cylinder with water.
After a while, the used top part will be dry and the lower part with gas will remain wet. The wet portion tells you the amount of gas left.
Most times we shake our gas cylinders to check if it is finished or not. That is a very dangerous thing to do. It could be suicidal.
Kindly share with friends and family.