I have always had allergy/sinus problems... recently I began to 'irrigate' my sinuses with warm salt water, which seems to help a lot... but when I am irrigating I noticed that I cough up mostly clear mucus that contains a few black "specks" about the size of my pinky fingernail. Any idea what these might be? I don't smoke.

I don't know, but I think you should see a doctor. That doesn't sound normal.

Interesting post for me to read. I wrote one myself about the black specks that I am spitting up, in the morning especially. My doctor told me they were due to post nasal drip and to not be worried, but I was (I smoke). I have Vasomotor rhinitis which means I have insufferable sinus trouble too. I personally cannot stand to irrigate my sinuses but I'm sure if I did I would see the black specks then, and not in my spit!