So, anytime I get a used controller or game system, I do a thorough cleaning. This typically consists of a complete disassembly and soak in hot, soapy water after taking out the electronics, of course.
Out of maybe 15 consoles and at least twice as many controllers, I've only found two to be truly disgusting. A couple years ago, I bought a 32X on a whim because it was cheap. It smelled like cigarette smoke and took extra time to clean. It also had a few dead cockroaches, pretty gross.
The second was a PS3 I bought only a few months ago. It's a super slim, and again, I got it pretty cheap. This one also smelled like cigarette smoke. I didn't even bring it into the house until I was ready to clean it. Good thing too. Every part I took off was covered in roaches and roach feces. There was also a lot of insect "flakes", I guess this was some sort of molting? I almost threw the whole thing away several times, but I didn't. I even washed the boards because it was all so gross, yuck! What surprises me the most is that this is my newest system. I bought a 2600 about six months ago and its over two decades older. Nothing gross in there but dust.
Do you guys clean your stuff when you get it? Because of these two experiences, I won't be buying anything that smells like smoke in the future. What's the worst you have seen?