According to Wiki, "  The vibranium in the shield grants it unusual properties, allowing it to absorb virtually all of the kinetic impact from any blows that the shield receives without injuring Rogers in the process. The vibranium is also a factor in the way Rogers throws his shield: he often uses it to ricochet around a room and strike various opponents with little loss of velocity in its forward movement after each impact." 
In DoomWAr#4, TaChalla gets rid of all of Earth's vibranium, but Cap still has his shield-WHAT GIVES??

Well at least someone tried to answer my question.

Also, Cap's shield isn't pure vibranium. It's an amalgam of dozens of differing elements that can't be replicated. It's possible that even if BP did neutralise all Vibranium, Cap's shield wouldn't be affected.

" @Osiris1428: Black Panther didnt get rid of all the EARTHS vibranium he neutralized all of WAKANDA's vibranium "

" Also, Cap's shield isn't pure vibranium. It's an amalgam of dozens of differing elements that can't be replicated. It's possible that even if BP did neutralise all Vibranium, Cap's shield wouldn't be affected. "

" @FadeToBlackBolt said:

" Also, Cap's shield isn't pure vibranium. It's an amalgam of dozens of differing elements that can't be replicated. It's possible that even if BP did neutralise all Vibranium, Cap's shield wouldn't be affected. "

Dang you beat me to it.  Why do people always forget it's an alloy. "

From what I understand, when Doom got a hold of the vibrianium he was able to control the trace particles all over the world. So when T'Challa got rid of it, he got rid of all of it off of Earth, @FadeToBlackBolt:  
Do you think he should get it back? Doesn't getting rid of it plunge his nation into poverty. Also: He should have killed Doom!!