I have a new computer and want to use itunes homeshare. I have found that there are already 5 computers sharing , of which I know 3 aren't being used (scrapped) so i can't just log on to them , to deactivate them. Can i do this remotely ??
From this Apple Support article you can do it from your account however the caveat is you need to de-authorize all of them at once.
Step by step instructions are available in the linked article. Also note the following: