I'll respectfully disagree with the others about soap. Using a detergent is a good idea as it saponifies various fats into solution.
As long as you're using mild, unscented soap, I think it has its place, especially when cleaning plastic buckets.
I notice that mild soap and hot water removes various compounds (e.g., oils) that oxyclean might not remove as well.
Oxyclean is predominantly a cleanser, though it does contain non-ionic detergents.
I do wonder about its effectiveness in various water profiles (like mine which is high in sulfate and bicarbonates).
Regardless, rinse well after using soap or oxyclean and do not do prolonged soaks for days on end with oxyclean and water with high bicarbonate levels--you'll get a residue that cannot be easily removed from SS and impossible to remove from tubing or plastic.