They woudn't. Dollars-to-donuts the writer was wrong. An open tray of gasoline used in
such a fashion is an absolute disaster waiting to happen -- google "garage fuel vapor ignition"
some time to see why. (Never mind breathing the stuff)
never, Never, NEVER use an open container of gas for cleaning anything. If you've nothing else
(and we all find outselves there once in a life), wet a rag with some small amount of gas -- close
and separate the gas can from you -- and gently clean the parts.
Better yet, go get some paint thinner/mineral spirits -- and even then close & separate the
container from you. (It's the main ingredient in charcoal lighter fluid -- take the hint)
Best -- go get a gallon paint bucket of automotive parts cleaner, which is what you really
wanted in the first place.