Digging inside my father wardrobe, I found a really old hard disk. If sticker on it is correct, it is over 15 years old and wasn't run for at least past ten years. It is still on ATA strip, but it is put inside 3,5'' box case with USB 2.0 cable.
Is there anything special I should do or take into consideration, before powering this up and connecting it into my computer? Is there anything that could damage the disk or data on it only cause it wasn't powered for past ten years or more?
Nope. Power it up. It's not like there's a bike chain in there you need to grease. If it doesn't just work you could try the freezer trick. Other than that, unless there's data on there you really need, I'd just toss it if it didn't work the first time.
http://lifehacker.com/5515337/save-a-failed-hard-drive-in-your-freezer-redux
I still use a 13Gb disk from 1999 for storage of stufff that i don't need to access very often, and it works like a charm. I too have it in a USB case.
No special considerations to take, just be aware that drives weren't as robust as they are now when it comes to rough handling.
