Deactivating old computer, itunes match

I just bought one of the new MBP retinas and it only has a 500GB hard drive, so I want to store all of my music in the cloud using iTunes Match. I am now in the painful process of uploading all of the music from my old MB to iTunes match, and I hope to be finished with that in the next few days.

My question is this. Once I have everything uploaded to Itunes Match and have backed everything up from my old machine to an external hard drive, is it safe to deactivate my itunes account on the old machine and wipe the machine clean (i.e. reinstall the OS) as I want to get rid of it? Basically, I just want to ensure that by wiping all of the data off of my old machine I'm not going to inadvertantly wipe everything off of iTunes match, so if the music does not exist on my new MBP will it still remain in the cloud for me use on my new MBP and iPhone?

Does anyone know the proper procedure for doing this? I don't want to mess anything up, but I don't want to have to keep the old machine until the end of time.