My friend called me over to check out her clogged kitchen sink, eventually I had to take it apart to the pipe going in the wall. Nothing would budge the clog. I used a shop vac and sucked out 2 whole pecans. I believe they were dropped in there by the previous renter. Her sink drain has no cross bars to protect large objects from going down it. If there are two, I'm sure there is more. Water still stands in the pipe. I couldn't locate a clean out any ideas?

You could call a professional to come snake it out with an auger bit or try to rent one yourself. That should cut through anything including roots that may be blocking the passage to the sewer.

Califdadof 3 is right in cleaning out the drain and use a cutter head. However, do pecan trees shade the house? Did the pecans still have a husk on them? I found some in an elbow after they fell down the roof vent. If that's the case, put a mobile home vent cap on the pipe.

Both above answers are dead on. I would also suggest replacing the sink strainer basket so no large objects can enter the sink drain in the future (just a plugged drain waiting to happen.) If they decide to call in a pro, I would suggest a plumber, as they would be able to auger the drain, and replace the strainer all in one trip(as long as you let them now to bring a strainer basket).