Computer removal in AD

I want to do some housecleaning in AD, and I want to remove any old computer names from the computers list in AD. I cant find anything that does this automatically, so I was thinking I could do this when no one is working…

Turn all computers on the domain off, then delete them from AD. If my assumptions are right, AD would then repopulate itself as I turned the computers back on.. Right?

I dont really care about permissions I had assigned the computers already, as I understand this would be like a new computer to AD..

Please let me know if anyone has any ideas!

Thanks