Assuming this is an injected car, disconnect the pressure line from the injector rail (once the tank is empty) and blow the fuel back into the tank using compressed air. There could be enough crud / sediment in the fuel feed line to plug the injectors. Of course, replace the filter before refueling.

Another tip would be to run a piece of stiff wire down the filler neck until it hits the bottom of the tank, scrape it around a bit, and pull the wire back out. If there is brown goo on the wire, your tank should be cleaned out as well. Stale fuel "normally" has a sickeningly sweet smell to it and smells nothing like gasoline.

Spoiled/stale fuel can cause all kinds of problems if it is run through the engine:

Plugged injectors / carb
Plugged fuel regulator
Stuck intake valves (very ugly)... depending on engine design, at minimum, the head needs to come off.

jorrell

Not to overstate the obvious, but best done outdoors. Don't know about your garage, but if connected to the house, would hate to have the gas vapors ignite(ie hot water heater or furnace pilot light.)
Had a troop fill a Coleman lantern while smoking. We got there 5 minutes later to a smoking ring on the ground where the command tent used to be. He survived the fire, but I'm not sure if he survived telling the commander what had happened!

Yes, please let us know what becomes of the fuel you drain from Inga.

Just pull the screw out of the bottom of the tank and drain it. Thing could hold as much as 16 gallons and it will take awhile to drain it through that hole, have fun.

Mark