I filled up a new parts washer with a solution of this & have cleaned the valve covers to one of my project vehicles with it. Overall, I would say that it works very well at cutting through caked & baked-on motor oil. The only drawback is its cost, but it should make up for that some by being able to reuse it several other times.

If it cost a little less, then I would have given it five stars throughout. Overall, I would still recommend this to a friend.