Cleaning Retro Game Cartridges

I picked up a couple games at my local game store. Before I put them in any of my systems, I need to clean them up first.
I'm going to go through the basic steps of cleaning cartridges before I put them in my collection. My game systems are already cleaned, with grime free pins & connectors. By cleaning up my games before playing them, even the working ones from the store, I can be sure my systems will stay clean and working for years to come.