You wont.... they'll dig themselves out
if they are in there which is probably unlikely.
I have a patch of soil that held a compost heap for years - the soil is wonderful there - presently I have a small stack of old timber (remnants of a replaced shed) there along side of a path.
There are now four fox holes! Despite filling in and poking barbed rose-prunings into the holes the foxes keep coming back for more and digging it all out again.
I had thought of setting up a hide and going into business offering "nature view" sessions for those so inclined to turn up late with a torch and a flask.