You are mixing a Acid (Citric) and a Alkaline solution together, If you have not checked the MSDS of the Castrol a FYI. I would think it not brass friendly over time. Mixing a Lye containing product with a acid can cause serious health issues.
http://deltaindustrial.com/MSDS/Clea...SuperClean.pdf
The basic solution of several cups of white vinegar a few tablespoons of salt and a drop or so of dish soap mixed with water makes a pretty good cleaner that is safe and cheap.
No,you will not need sunglasses for a bright shine but certainly clean enough.