The effects of OLD gasoline in a classic car

Gas tanks for cars with carbs are 1) ventilated, and 2) sit outside in whatever ambient, from 35 below to 110 above, breathing the same air you and I breath, with every change in temperature. If that air happens to have moisture in it as often it does, then that too will get into the gastank..... while 3)the VOCS are constantly abandoning it.
But yur right the gas tank is dark, so what; this is a color test.
I know you know this so why are you ragging on me again? Go have a beer.