FSX-MS How do I kill off an airfield?

[pallelli 4]

I've been flying FSX for more than a few years, and overtime some airfields have passed into history. This became a problem for me when I tried to add in Old Wardon airfield to FSX, Old Wardon is home to the historic Shuttleworth collection - well worth visiting. The problem is that the airfield has the ICAO code of EGTH, the same as the former Hatfield aerodrome. Hatfield still exists in FSX world (with the code EGTH), but it has disappeared from the real world. I can change Hatfield's ICAO code to something else using Airport Design Editor, and I can delete all its runways etc, but its still there in FSX. I have a similar problem with Woodford (EGCD), and to a lesser extent Filton (EGTG) and Lyneham (EGDL), which is the nearest airfield to my home. The latter two are closed but still have extant runways etc, but is there a way to eradicate old airfields?

Edited June 19, 2020 by pallelli
Make it better

[Gridley 257]

See here: https://www.fsdeveloper.com/forum/threads/tutorial-how-do-i-remove-a-stock-airport-from-the-sim.433601/

I'd offer to help, but I don't have FSX installed any longer...