My phone got wet and now it won't charge and there is black stuff coming out?

Make an appointment at the genius bar and get an out of warranty replacement. You've destroyed it. It is NOT safe to use. Put it in a fire safe container, preferably outdoors, and do NOT attempt to charge it or use it again.

Hey there, I'm sorry this happened to you.
Let's be practical. What is coming out of your phone is likely just wet pocket lint that is common to every iPhone 6 charge port. The charge port itself is pretty isolated from the inside of the phone, and it commonly fills up with pocket lint, sawdust, grass clippings, cat hair etc. I can understand that you're concerned that you might have battery acid or something dangerous building up in your phone that is squeezing out the charge port---but there really isn't a mechanism for anything like that. There is no battery acid in an iPhone 6.

What happens to an iPhone 6 with your history is that a drop of conductive water will penetrate the housing, and roll around for awhile until it slips under the logic board and finds its way to C5202_RF--a well known capacitor on the main power rail. Once that happens, the water damages the capacitor so that it become a wire to ground. Quickly after, your entire battery voltage will dump to ground and the phone may get hot briefly. After that--your phone is dead unless you find a repair shop willing to troubleshoot your logic board to relieve the short (most will not work on water damaged boards since they can be very open-ended). From experience looking at thousands of water damaged iPhone 6, if we opened your phone we'd see some corrosion on the logic board, a dead battery, and some drops of wetness. If data recovery is important, then the chance of getting this phone to boot for data is very high. But to be a phone again---you're probably out of luck.

The Apple Store will accept any water damaged phone for out of warranty discount--and sell you a refurbished iPhone 6 for less than the cost of a new one.

When an iPhone 6 hits water, one of two things can happen.

One--Water doesn't penetrate into the phone, or if it does it rolls around on the battery side of the phone and eventually dries up.

Two--water finds it way to the logic board where now electricity and water combine. From there, it can corrode components, rot connections under chips, and eventually cause a short circuit that makes the phone stop working all together, or lose some functions.

In general it is never a good idea to plug a phone in that has been wet until it has been cleaned. Water isn't the problem, ELECTRICITY plus water is. If you are in category one to begin with, you want to stay in category one! The easiest way to do that is open the phone up, disconnect the battery and clean up any water and mild corrosion before it has a chance to become a problem. The Apple Store will not do any service on a water damaged phone, and many repair places will not either---no one wants to open up your phone, see that some component is held on by spit, clean it and then have it fall off and your phone stops working---then you will point a finger at them and say "You broke my phone!"

You might be able to find a shop that has good reviews (there are a lot of bad shops out there, like any service industry) that is willing to open your phone and see what they can do to clean it. Keep in mind that 80% of the logic board is under soldered-on metal shields. The labor to desolder the shields and to check out and clean under there is pretty extensive, so most "water damage cleaning service, no warranty" are just going to spot clean the edges of the logic board.

If this had just happened a few minutes ago and you hadn't yet plugged the phone in, then yes--go to someone who can open your phone and dry it out. At this point, I think you're just playing roulette and hopefully you'll get lucky!

Contact Apple or an authorized provider to have the phone replaced.

Make a Genius Bar appointment at the nearest Apple Store and be ready to purchase an out of warranty replacement. DO NOT attempt to use the device again.

In all likelihood, you have destroyed it. Make an appointment at your local Apple Store for them to examine it.