i just bought a pr3 intake manifold to be used in a swap, but there is a black oily residue all over the inside of it. it really has me puzzled as to what could have caused this and how i can get it out. i don't want to run this intake with all the crap inside of it but don't know how to get it out. if any body knows what could've caused this i would like to know also if anyone knows how to get it out, please help. its all over the backside of the Throttle body too.