diff --git a/klippy/klippy.py b/klippy/klippy.py
index 187b45e5..03095d06 100644
--- a/klippy/klippy.py
+++ b/klippy/klippy.py
@@ -1,10 +1,10 @@
 #!/usr/bin/env python2
 # Main code for host side printer firmware
 #
-# Copyright (C) 2016-2018  Kevin O'Connor <kevin@koconnor.net>
+# Copyright (C) 2016-2020  Kevin O'Connor <kevin@koconnor.net>
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
-import sys, os, optparse, logging, time, threading, collections, importlib
+import sys, os, gc, optparse, logging, time, threading, collections, importlib
 import util, reactor, queuelogger, msgproto, homing
 import gcode, configfile, pins, mcu, toolhead, webhooks
 
@@ -312,6 +312,7 @@ def main():
         if bglogger is not None:
             bglogger.clear_rollover_info()
             bglogger.set_rollover_info('versions', versions)
+        gc.collect()
         main_reactor = reactor.Reactor()
         printer = Printer(main_reactor, bglogger, start_args)
         res = printer.run()
@@ -319,6 +320,7 @@ def main():
             break
         time.sleep(1.)
         main_reactor.finalize()
+        main_reactor = printer = None
         logging.info("Restarting printer")
         start_args['start_reason'] = res