The pin stored in the grip is to secure the mainspring for disassembly, if you lose it a straightened out paper clip works fine.
Someone mentioned Flitz and someone else said something about harsh chemicals, Flitz is not an abrasive or harsh on metals, most bore cleaners are a lot more harsh than Flitz, but you certainly don't need much to remove the rings from the face of the cylinder. I really wouldn't consider a wheel cleaner for such a purpose, they are very harsh, and many of them contain acids, that's why the instructions usually say something about rinsing in 30 or 60 seconds, if they set too long they can etch the wheels, so I sure wouldn't use anything like that on my firearms! Those lead remover cloths will easily remove the rings on a stainless revolver, they can also remove bluing on blued revolvers, so they aren't recommended there.
The rings on the front of the cylinder are a cosmetic issue only.
