Having done this many times, I can highly recommend using the jumper wires. If your fuel system is in generally good shape (i.e. no leaks and a correctly functioning pressure regulator), then the fuel rail and lines to the injectors and CSV are all under quite a bit of pressure. So, if you just remove a piece (e.g. the CSV valve) without relieving the pressure first, fuel goes squirting all over the place. If there are no live electrical connections (disconnect and perhaps even remove the battery, to be safe), and you're not smoking, it would only make a fairly smelly mess, as opposed to an explosion or fire. With a rag over it, you can contain the mess. I've done it without the wires, mostly out of laziness and hurrying. But the jumper wires are so quick and easy to use to open that valve and relieve the pressure, and eliminates a lot of mess and trouble, that it's really worth it.
good luck,
Dave