I think that the consensus is that Optimum Power Clean is one of the best all purpose cleaners. It is known for being strong, yet safe, especially on sensitive materials such as leather or paint. Now, the drawback for using OPC is the price. Quite frankly it is one of the most expensive all purpose cleaners on the market.
That being said, it is also an APC that doesn't use harsh chemicals and is safer to the user and the environment than many others. If that is important to you, then I would say that OPC would be the one to go with.
Now, since you have the Purple Power, I would start off with that, mainly because it is the cheapest. On something down and dirty, I want to use the cheapest all purpose cleaner/degreaser first, rather than the expensive stuff, like OPC.
Regardless of what you do, please remember the proper protective equipment and at the very least, gloves. If there are fumes please wear a mask or respirator. You don't want to have the potential health effects that many of the chemicals can cause, especially when something as simple as gloves can protect you!
Happy detailing! :rockon
