ASP.NET temporary files can quickly mount up and eat up disk space, especially if you deploy multiple times a day. This website provides a handy command that you can run to delete any unnecessary files:
Get-ChildItem "C:\Windows\Microsoft.NET\Framework*\v*\Temporary ASP.NET Files" -Recurse | Remove-Item -Recurse
You’ll get a few errors when it hits files in use, but apart from that it works a treat. You can run this as a scheduled task if you want to avoid having to do it manually all the time, or get your deployment tool to run it on every deployment to tidy up as you go (Octopus Deploy has its own library task to do something similar, for example).