Car mechanic in the house

There are a few giveaways that my eldest is working on his car, this lovely oily hand print on my front door was the first, a missing kitchen roll and a line of cups with hand prints on in the kitchen being some of the others.

His 15 year old Corsa has just been through its MOT, it failed but not too badly and has now passed but he is now doing a service to it, oil, filter change etc to keep it ticking along for another year.