Clean up WSUS space usage

See your server with too much space used by WSUS?

This link has a good method
https://social.technet.microsoft.com/Forums/en-US/278dfa59-aba4-4442-bbbe-6cd68fd725d8/sbs-2008-wsus-content-folder-is-over-20gb-how-do-i-decrease-this?forum=smallbusinessserver

The nut is this, by SuperGumby, quoting:

• You'd probably each do well to open up the standard WSUS console, Updates, All Updates, and expose the supersedence column (rt-click on the column headings to do so).
• Set 'approval' to 'any but declined', set 'status' to 'any', refresh the list, and sort by supersedence.
• There's probably a few thousand updates in there that are either 'superseded' or both 'supersedes and is superseded'.
  Decline the lot (of superseded), run the cleanup again.
• You have to look closely at what the cleanup task says about cleaning up superseded updates to understand why these are left alone.