I tried to do a clean install of my El Capitan MacBook but realised that much of my keychain migrated over. When I went into keychain access it showed a number of different keychains. I reset the "login" keychain which seemed to delete the "iCloud" keychain as well. However, "local items", "System" and "System Roots" all survived. Should I clear these as well?
Before I did the clean install, I know there were a few times when I was confronted with having to trust an unknown certificate. I want to make sure these are deleted. Which keychain would these user-trusted certificates have gone into? I want to make sure that certificates that I decided to trust are deleted so that I am only left with certificates supplied by Apple on new machines.