The two most disgusting things in the world are remote controls and video game controllers. I'm not sure which is worse. You can't always tell until you take them apart. Seriously, eww.
But some controllers have been around for a long, long time. The ColecoVision was released in 1982 and discontinued in 1985. That means that any official controllers out there are 28-31 years old. If they haven't been cleaned (and honestly, who cleans their controllers?), they're probably pretty gross by now. And let's face it, they pretty much combine video game controllers with remote controls. So let's clean one.
Step 1: Survey the Grime
First, let's take a good look at the work ahead of us. There's likely a lot of gross stuff all over the controller. Much of it is dead skin cells. Perhaps some of it is soda. Much of it may be cheese. Who knows. Give it a good look over. Then call your mother and tell her that you love her.
Step 2: The Equipment
Okay, now that you know what you're up against, gather your tools. You'll want a phillips head screwdriver, some pliers and a toothbrush. Mine's electric, because I'm fancy. Note that this is the equipment for the best case scenario. If your ColecoVision controller is flaky or unresponsive, you may need to repair it, which is much more involved. This instructable will not cover repair, but I may make one later on.
You'll also want some dish soap and a container of some sort to soak parts in.