Deleting OLD files in winsxs

Install the following update:

Disk Cleanup Wizard addon lets users delete outdated Windows updates on Windows 7 SP1 or Windows Server 2008 R2 SP1

Run Disk Cleanup and now you can uninstall updates (Windows Update Cleanup) which are replaced by newer security updates and are no longer needed. This can save several GB of space.

You can't get rid of them at all. Many programs are using older versions of the Visual C++ Runtime (and other libraries, of course), for example. That's what this folder is for. It's perfectly normal for it to be many gigabytes in size.

Be aware though that the folder consists of many hard links, so not all programs are able to correctly calculate its size.