Everytime you carwash your ride, use a wet cloth and wipe around your engine bay, under the hood, hoses, and any components that you can reach. You dont have to rub it hard or anything, just wipe it. After 5 years, your engine will always look new. Make sure you do this when the engine is cool to touch. You dont need to spray, just do it little by little. It will take about 10~15minutes of your carwash time. Just use water, do not add any detergent or anything else.

For the interior, I'm in your situation, I cant do anything but to take good care of it.