How to dispose of a car I put a mechanic's lien on?

I have a car that I have placed a mechanics lien on. The owner refused to pay for repairs and stopped returning phone calls. I have taken steps to notify the customer/owner of impending sale/disposal of the car. At one point I had a buyer interested in the car, but I have been unsuccessful in getting a title through the state of Illinois. At this point I want to dispose of this car properly. It is an older car, not worth much money and it's been sitting in my back lot for almost 2 years. What do I need to do to be able to junk the car? Is it possible to get a Certificate of Purchase on such a car? or will all my doentation and mechanic's lien be sufficent? I want a paper trail. I have done a title search through the state and know there are no other liens on the car.