How to clear a massive Windows C drive full of update bloat

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

1. 1
   Trying to uninstall and reinstall certain applications like Adobe Acrobat Reader to reduce swelling installer data in system folders
2. 2
   Telling users to manually delete files in specific folders
3. 3
   Making compliance a company policy with HR involvement and consequences after a grace period

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.