Whatever you do, don't swallow!
The best option is to buy a new electric car or get it professionally converted. Working with battery fluids can get dangerous and expensive. Keep the gasoline car to save the environment.
A good example is the way gasoline is used in a car.
The way to drain gasoline from a Briggs and Stratton lawn mower is to take the oil cap off and drain the oil. From there, run a rubber hose into the drain and siphon the rest of the oil and gas out.
This task can be accomplished best by siphoning the fuel out of the tank itself with a siphon pump into an approved container for transport or storage. If it is filled with gasoline, the best way to get the tank bone dry is to leave the fill opening unsealed so the remaining volatile liquid can escape on it's own.
Run it out of oil.
The best way is to siphon the old out and pour new in.
The same way a gasoline car does, albeit with a different fuel type.
The best, fastest and easiest way is to let the pump siphon it for you directly from the big tanks. Go to your local gas station and pay, then the pump will do all the work for you. :-)
Gasoline is a nonrenewable resource.
The purpose of a gasoline car engine is to convert gasoline into motion so that your car can move. Currently the easiest way to create motion from gasoline is to burn the gasoline inside an engine. Therefore, a car engine is an internal combustion engine -- combustion takes place internally. The engine turns the explosion that takes place into Horsepower & Torque. Torque gets the car moving and Horspower keeps it moving.
When a siphon flows the wrong way.
The best way is to siphon it out. The 1961 shop manual has detailed instructions on how to do this. Followed these and it worked fine.