It's the easiest way. I use a suction gun to empty the master cylinder, refill with clean fluid and bleed until all the bad stuff is gone. I bought a piece of 3/16" clear plastic tubing at the hardware store, long enough to make a loop and reach the floor. One end on the bleeder screw, the other in a clear 2 liter pop bottle. Put top of the loop above the wheel cylinder. Makes it easy to watch for air bubbles and contamination. And be sure not to let the master cylinder run dry.

When I was first in the business the shop I was at still had a fill bottle. It was a glass bottle with a valve and an adapter for the m/c that screwed on the m/c and kept it full. It wasn't used because we no longer did any work on vehicles with small master cylinders.

Fred
52 3600
69 C-10