Repairing/cleaning a NES

[Falc]

I'm feeling nostalgic and thinking of trying to get my old NES to work. The last time (~5-10 years ago) it wasn't tucked away somewhere it didn't work but the last few days I've been reading some on the net and it seems that in most cases they stop working is because the systems/cartridges aren't clean.

So I'm thinking of trying to clean it up/repair if necessary and hopefully it will work so I can enjoy some really good games for a change.

Anyways, anyone has any experience of doing this? There are some guides on the internet and most of them are the same so the doing the basics shouldn't be a problem. I'm more curious about some pitfalls there might be. Like, if you unscrew that that screw the system will never ever work again [img]/images/graemlins/smile.gif[/img] Well you get the idea atleast. Any takers?