How do companies handle work schedules no longer used by the business?

We have a lot of work schedules the business is no longer using. We would like to remove them from the list of work schedules that can be selected. Apparently the only way of doing that is by removing all employees from those schedules. This is not practical since it will impact any absences that were submitted in the past.

I am very interested to find out how other companies are handling this scenario.