If he doesn’t need the office, let them sit there out of the way. Otherwise, arrest the trespassers.
Spot weld the office’s doors and windows shut.
Turn off all power and water.
After eight years send in a HAZMAT Team to clean it out.
Buy the building.
Burn it out; bull doze the rubble and turn it into the Jeff Sessions and Donald Trump city park.
Did I miss any thing?
I suggest turning the power and water off. Note to Paul Ryan: works on house members too.