When you remove the fuel pumps from a 560 SEC, you have the opportunity to have a gasoline shower, with the fuel running down your arm and thoroughly soaking you, clothing and all. I don’t recommend you pursue this particular style of self-destruction.
The alternative I choose is to jack up the passenger side rear wheel, way high, and to place an axle stand under the suspension component close to the wheel. Then, I place a container underneath the fuel pumps, and then slightly loosen a connection so that the fuel drips into the container, thus emptying the tank. That way, I don’t have to deal with as much of a gasoline mess, when you take the pumps out. There will still be some gasoline and pressure, but it’ll be a better situation than if the tank contained a large amount of gasoline.
I suspect that I could also have used the drain plug at the bottom of the tank, but draining it at the hose I’m supposed to work with tends to make that critical area better-drained.
Gasoline and static electricity tend to make for a big fire. And, gasoline being drained does, according to one story I’ve read, build up a static charge that can trigger a static spark that can burn down a building. So, I ground the car with a steel cable from the negative battery post to the floor.