Brooder- how old is too old?

Our (well, MY) first batch of chicks is on order and should arrive in mid-July. My husband had chickens for a while as a kid and we have an old brooder he used to use. I don't know its exact age, but he had chickens back in the very late 70s- early 80s. It's a metal brooder with a thermostat. It's not particularly rusty, but I am concerned that I won't be able to properly clean it up and disinfect it. I don't really even know HOW to clean up and disinfect metal/steel/whatever it's made of. I can't just hose it down with anything because the thermostat is built in. I want to just say "Forget it" and make a new brooder, but if this one is perfectly functional and able to be properly cleaned, then we probably should. He tried to incubate quail eggs in it a few years ago (I know, it's a brooder, not an incubator, but he was determined to try and no, it didn't work ) and the thermostat worked then. Of course we will clean it up and get it set up before the chicks arrive and make sure it's functional, but has anyone had success with an old brooder? Should I try to talk him into a simple heat lamp/plastic tub brooder and forget this old thing?

I am already nervous as heck about being a chicken owner. . . my husband is no help as he raised his such a long time ago, and his lived in cages and didn't ever go outside, so when I talk about bringing them inside the coop at night, he looks at me like I have three heads. He's like, "Won't they just sleep on a roost, within the pen, at night?" I said, "Nooooo. . . you have the coop so they can have nestboxes to lay their eggs in (hopefully) and to shield them from predators and the elements. Then they're let out in the morning." I don't think he has the slightest idea HOW keeping a backyard flock has evolved within the past couple of decades. I'm trying to explain my ideas of how I want to raise them.