I would only do this under an account other than one with administrator permissions, so you change these permissions at your own risk.
Go to each individual folder, right click, choose Properties, go to the Security tab, choose the Advanced button at the bottom, find the user account you want to modify permissions for in the Permission Entries window (I would not choose and administrator account here), click on the Edit button, choose the Delete checkbox to explicitly deny deleting of files, and click OK all the way out.
This should work, but I can't really say how it's going to affect keeping the cache size for that user account in check as this is not something you'd typically do for temporary cache folders. These folders are designed to overwrite older/update files, so this may break them to an extent.
This will only work when the user account you chose is the one they are logged in as and using.
As I said, this is done at your own consequence.