i bought a little hand pump with a reservoir at auto zone for bleeding clutches, brakes, etc... about $35. just get one of those (nice to have anyway) and loosen the slave bleeder, remove the master cap, fill it all the way up, and use the pump to suck out the old fluid. make sure you have plenty of fluid in the reservoir while bleeding, or your suck the reservoir dry and just introduce more bubbles in. should be a 5 minute job.
... or do it the old fashion way with 2 people and have one press the clutch while the other opens and closes the valve.
OEM/Liquid siphoning vacuum pump kit (25136) | Vacuum Pump Brake Bleed Kit | AutoZone.com