black discharge from eyes

does anyone know what causes a a discharge from the nose and eyes that becomes black and crusty? The vet doen't have a cure, and the pet shop guy sells stuff to clean it, but not to stop it in the first place. On antibiotics for a different reason it improved, and a flea collar made it a lot worse. She's had this since she was a kitten, she had cat flu when I got her and the vet suggested this damaged her eye ducts which causes the discharge. Anyone got any ideas?
Sarah

Both of my cats get this, if its the same thing you are talking about. My vet says its normal, and to just wipe it with a warm wash cloth when it becomes visible. Maybe you're kitties have the same thing. There are others here that are much more knowledgeable, and I am sure will post to you also.

My Loki also at times get that goop - I do the same as dtoll.

Most cats who develope any sort of infection as a kitten become carriers and when stressed, they shed and sometimes develope symptoms. The discharge will come and go, just make sure there aren't any other signs that will need antibiotics.

My cat has the same issue with the black stuff coming out of his eye's...We did happen to notice it gets alot worse when we put a new flea collar on him....makes me wonder if he has an allergy to the collar...?Anyone else also use flea collars and your cat has this black eye stuff going on ??

It's normal.  It's just like you get "sleepy" in your eye, so does the kitty.  Nothing to be concerned with unless it because a lot of discharge or if it becomes yellow or green.

My cat is almost 19 years and recently developed a very dark discharge out of one eye. Also noticed some at the nostril on the same side, but minimal. I tried many things and read as much as I could find without much help. I racked my brain for ideas and it occurred to me that this change coincided with a change from wet to dry food (he prefers, and I was trying to get him to eat more calories). I started rinsing his dry food in a strainer before giving to him, and the problem has resolved. So in some instances, it may be diet-related and the food choice the culprit. Can't prove that was the case here, but it worked for me.  I have degrees in medicine and nutrition.