Last year having displaced the extension needed to get the gas in my car, I removed the cans spout, elevated the can above the gas tank and siphoned the gas in.
These cans were designed to prevent spills if the can tips over but we all know you spill more gas when it blurps from the unvented can in using it.
I've often said that when the government official who mandated these cans dies and goes to hell that he should have to spend eternity using these cans.