Maintanace for the SHA1 folder in an Isolated network

Hey guys
looking for help on the following issues

I have an isolated environment ( servers 2008, 2012R2 2016, worktastions w7 & w10 )
problem is my SHA1 folder is already at 1.3 TB in size
is there any normal way to control the quarterly downloads inorder to not download fixlets that are not needed

is there a way ro run maintenance on the SHA1 folder to delete obsolete fixlets and fixlets that are not needed ???