I have an Opel Corsa D built in 2012. My father kindly wanted to treat me on the weekend. I bought extra underbody wax for it. Before I knew it, however, my father put used oil (old used motor oil) on the underbody with a compressed air paint spray gun in the front area of the car (wheelboxes, engine compartment). I then shocked him that this is forbidden nowadays and that waste oil is toxic. I now make myself responsible for several points. 1. Waste oil contains highly toxic substances such as heavy metals and toxic hydrocarbons. When spraying, a real steam cloud has formed, which has emanated from the cracks of the bonnet upwards. I am very worried that these toxic substances can now also penetrate the inside of the car via the blower / air conditioning system, since traces of waste oil may also have found the way to or into the air intake. 2. Waste oil contains certain substances (acid Ver 3. Waste oil attacks rubber or plastics. I am concerned that the respective parts will be eaten. Once I have noticed this (the front part of the car has already been treated), I have immediately subjected the vehicle to an underfloor washing machine in a nearby car wash, but this will not be able to undo the process. I am very happy to be able to do so. Do I have to worry that the blower will cause harmful heavy metals or other toxic compounds to enter the interior? Does a maintenance of the air conditioning system from the specialist workshop help here? Do I have to worry that the rubber/plastic parts in the engine compartment/wheelboxes will now be damaged?