Uninstalling in just one sim won't save you any hard drive space now, since the location is now shared between all the sim. So, rather than uninstalling, you will probably want to temporarily disable them, so you can do that using the "Options->Add-ons" menu.
Note that, the "Options->Add-ons" is not the same as the "Addons" menu. And, it will also allow you to disable executable modules from starting, not just sceneries.