Terry
If you can tell me which miscodes have not been picked up in 2 years I can delete them, how would you know when a miscode was last picked up?
Thankfully entries no longer current have no affect on the database as they are only used to populate aircraft picked up, if they are not picked up there is no issue, just don't show
Most little ones usually only have one transponder so one way of identifying which is no longer used is to find out what one is being used now, however that means scanning the screen looking for the frame you are looking for.
Thanks again
Alan