All you have to do is just open up your chamber, spray a little in, close it up and hit the sparker. You need to use the aerosol type of hairspray, not the pump-action. This propellant is fairly good, but it isn't as powerful as others, and it might make your gun sticky. Note that hair spray only works well were it is hot and humid. You will notice that in cold your performance of your propellant will dramatically reduce.
Propane is actually a commonly used propellant.
It tends to give a good powerful shot without being a dangerous propellant. Propane is cheap, basically safe and easily dispensed. It is very cheap, as one bottle will give at least 1000 rounds from a typical launcher. A lot of people I know uses these. They should be easier to dispense than butane, and won't gum up your cannon.