Model diesel engines are well known for the smell and mess they produce. The mess can be taken care of on the model easily with long exhaust tubes, because the engines are insensitive to exhaust back pressure.
Inevitably, during starting and use, exhaust and fuel will get onto one's hands, clothing, and other things where the lingering odor is a nuisance. Most wives don't care for the "engine smell". You've probably found that
most soaps do not completely remove the smell and stain of diesel fuel from your hands. The answer is hair shampoo. Most shampoos will remove kerosene from hands. I have not tried it on clothing,
but it should also be effective there. Some hand soaps do work, my wife happens to like one of the Dove liquid hand soaps and it does work. I usually wash with another soap after to get rid of the floral scent.