What is the black stuff on this p/s hose

[SilverSoarer]

Power Steering works but is leaking.

Is this p/s hose gone and is the black residue a blown o-ring ?

[rusty9]

Thats an A/C line. could possibly be stop leak gunk. never seen that before

[GreenCohn]

NEVER use Stop leak freon in your car!!! It will ruin the whole A/C system.

[fenixus]

it looks like a leak from a/c system. on wife's 5s-fe the top of drier-receiver tank is same black oily nasty despite the fact that I replaced it (and lines to it) at a shop.

a/c refrigerant is mixed with oil, so if there is gas leaking, then there must be oil leaking out too. nothing unusual. top off every 2 years and ignore it ... unless you want to replace some parts.