Gunk in my beer?

I kegged for the first time and everything went well. I completely sanitized and cleaned the keg, but about every other beer theres a chunk of unknown black stuff. The keg had been sitting around for like 5 years without use or cleaning and the same thing with the CO2 tank. I'm using a picnic tap until my kegerator is up and running. The only thing i can think of is old beer in the dip tube that leads to the faucet that is coming undone due to the constant pressure. If anyone has any clue to what it is, where its coming from, or how to prevent it id appreciate it. Next batch i plan to sanitize and run the sanitizer under pressure through the keg out the tap. Is that how you would typically clean a keg?
Thanks,
Mark

Well, I bought my kegs already cleaned but I still cleaned them anyway. I removed the dip tubes, and cleaned them well with oxiclean. I also cleaned it inside with the oxiclean. I don't have a diptube brush yet, but I cleaned it inside and out and all those little poppits, too. There are only a couple of parts, so I just threw out the old orings and replaced them. Then I rinsed well, and soaked everything in star san. When I put it back together, I put the star-san in the keg, and shook it up well, and then used some co2 to push the star san out the beer line and picnic faucets. Then I just dumped the star san and filled with beer. I've never had a problem, and they are super easy to clean.

I would definately check the poppet and the dip tube. You should change the O-rings while it is apart.

Thanks guys. Where can I get o-ring sets.
Mark

Link to replacement o-rings

Check out the sticky thread "kegging FAQ's" at the top of the page. Some good links there for kegging questions.

Yeah definatly try replacing all the O-rings as well as the poppets, maybe the black stuff is from some rubber comming off from one of the o-rings.

also you should check inside your dip tube by holding the one end up to a lightbulb and peeking into the other end. you can actually see inside to make sure its crystal clear...

If you got it used and not super-clean...........

You need to take EVERYTHING apart and clean it. Soak everything in PBW/Oxyclean/etc. Rinse all the cleaning junk off very well and put it back together with new O-rings.

Check your disconnects, and clean them too. Everyone forgets about those.