I was recently surprised to find some sensitive data in my macOS clipboard that I must have unintentionally copied there earlier. This information could accidentally leak out as a result of an unfortunate or inadvertent paste in a shared Google Doc, for example. Moreover, there is an abundance of evidence on the Internet concerning clipboards as hacking attack vectors.
As a result, I have added the following entry to my crontab:
*/5 * * * * cat /dev/null | pbcopy > /dev/null 2>&1
pbpaste provide access to the clipboard from the macOS command line. This line results in the clipboard being regularly cleared every five minutes. It is possible you may be a little unlucky and have this command triggered in the middle of a copy/paste thereby losing your “copy”, but I am OK with that possibility for the security benefit.