If you want to flush out the whole system ( which you should do to your clutch and brake hydraulic systems every two years . If you did, you would basicallynever need to replace calipers, or master/slave /wheel cylinders . It's teh water that gets absorbed into the fluid that causes the damage over time, most all the European cars have this basic service listed in the owners manuals but the 'merican cars want you in getting expensive work done at the dealership )
best way is Get a motive bleeder pressure bleeder and pop it on the master cylinder, pressureize the system and crack teh bleder open at the slave and have a container to catch the fluid, let it run till it's all clean fresh fluid.