My father has obtained several vehicles with mechanics liens on them, as he owned his own repair shop.
Say a customer brings a car in for service. The shop fixes the car, but will not release the car until paid in full. If a period of time goes by without the deadbeat loser owner paying for the repair, the shop can file paperwork with the state that places a lien on the vehicle. This means that the shop has an interest in the vehicle, and ownership of the vehicle cannot change hands without the shop being satisfied.
If another given period of time expires, and with the proper paperwork files with the state, the shop eventually will be issued a title to the vehicle and can dispose of it however they choose, with no compensation to the "owner".
It is also legal for the shop to assess storage fees for the vehicle while the vehicle is on their property. So, it is wise for the owner to be responsible and pay the shop promptly, as the bill will do nothing but escalate.