Lueb,
Yes, you can bleed a hydraulic system in a number of ways. One tool that I've recently purchased is a pressure bleeder. You fill up the bleeder's reservoir with fluid and attach the cap to the MC. Then you pump it up to about 7psi. Next, you open the bleed valve on the slave cylinder until you get clean fluid or no bubbles, depending on what you're doing.
I have used a MityVac in the past to suck the fluid out from the slave end, but I find the pressure system a lot easier, especially for brakes, you don't have to keep running back to the MC to make sure there's enough fluid in the MC reservoir.
Other than that, you can use the pedal or gravity, but for $50 or so the power bleeder makes the job easy, especially if you have a number of vehicles to take care of.
Bogatyr