Every so often you will accumulate a lot of protections. Most of the time, a lot of these protections will belong to inactive players or they may have been protections on blocks that no longer exist.
You can cleanup any protections that do not physically exist anymore by typing /lwc admin cleanup. This removes any protections in mid air that do not have a block to actually protect at the coordinate. This command can be run often without any harm being done to existing proper protections.
You can also delete protections that have not been opened/accessed for a period of time. You can do this by typing /lwc admin expire [time period]. An example would be, /lwc admin expire 1 month. This would delete ALL protections that have not been opened/accessed after 1 month.