I have dicked with brakes for a long time and found 3 things that eliminate the fluid and air bubbles as being a problem..... As SWIGIN posted, there may be some rusty crap in the bleeder but the following will help you bleed them. Bleeding is a real PITA....
THE 3 METHODS FOR DIRTCRASHER:
1) Buy the real bleeder tool (I still have not bought one)
2) Ask someone in your family that is in the medical field or Vet field for some syringes. The medium size with a piece of tubing works great. I force fluid backwards from the bleeder up to the master.
3) "REDNECK BLEEDING TOOL" Simply suck on the hose while you crack the bleeder and spit it out like it's a snake bite poison.
Methods 2 and 3 are the reasons I never bought the right tool because they work for me. Method 3 leaves a bad taste in your mouth but works great
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country