diff --git a/janitor/ab-janitor b/janitor/ab-janitor
index 281d7b9..16a4d57 100755
--- a/janitor/ab-janitor
+++ b/janitor/ab-janitor
@@ -7,11 +7,12 @@
 
 import signal
 import os
+import subprocess
 import sys
 import threading
 import time
 
-tmpfile = '/tmp/.buildworker-janitor'+os.getcwd().replace('/', '-')
+tmpfile = '/tmp/.buildworker-janitor' + os.getcwd().replace('/', '-')
 
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'scripts'))
 
@@ -19,8 +20,6 @@ import utils
 
 ourconfig = utils.loadconfig()
 
-
-
 trashdir = utils.getconfig("TRASH_DIR", ourconfig)
 mirrordir = utils.getconfig("REPO_STASH_DIR", ourconfig)
 
@@ -41,22 +40,21 @@ def trash_processor(trashdir):
         return
     while True:
         try:
-            files = os.listdir(trashdir)
-            if files:
-                for file in files:
-                    file_path = trashdir + "/" + file
-                    file_age = time.time() - os.path.getmtime(file_path)
+            entries = os.listdir(trashdir)
+            if entries:
+                for entry in entries:
+                    entry_path = os.path.join(trashdir, entry)
+                    file_age = time.time() - os.path.getmtime(entry_path)
                     if file_age >= 60:
-                        os.system("nice -n 10 ionice -c 3 rm %s -rf" % file_path)
+                        subprocess.run(["nice", "-n", "10", "ionice", "-c", "3",
+                                        "rm", "-rf", entry_path])
                     else:
-                        print("Not removing '%s' - age is only %s seconds. There may be another process using it" % (file_path, str(int(file_age))))
+                        print("Not removing '%s' - age is only %d seconds. There may be another process using it" % (entry_path, int(file_age)))
             else:
-                time.sleep(120*60) # 30 minutes
+                time.sleep(120 * 60) # 2 hours
         except Exception as e:
             print("Exception %s in trash cleaner" % str(e))
-            pass
-        time.sleep(60) # 1 minute timeout to prevent crazy looping (particularly in age is only)
-    return
+        time.sleep(60) # 1 minute timeout to prevent crazy looping
 
 def mirror_processor(mirrordir):
     print("Updating mirrors in %s" % mirrordir)
@@ -65,18 +63,16 @@ def mirror_processor(mirrordir):
         mirror = ourconfig["repo-defaults"][repo]["url"]
         mirrorpath = os.path.join(mirrordir, repo)
         mirrorpaths.append(mirrorpath)
-        while not os.path.exists(mirrorpath + "/refs"):
-            exit_code = os.system("git clone --bare --mirror %s %s" % (mirror, mirrorpath))
-            if exit_code == 0:
+        while not os.path.exists(os.path.join(mirrorpath, "refs")):
+            result = subprocess.run(["git", "clone", "--bare", "--mirror", mirror, mirrorpath])
+            if result.returncode == 0:
                 break
             print("Failed to clone %s. Retrying in 30 seconds..." % mirror)
             time.sleep(30)
     while True:
         for path in mirrorpaths:
-            os.chdir(path)
-            os.system("git fetch --prune --all")
-        time.sleep(30*60) # 30 minutes
-    return
+            subprocess.run(["git", "fetch", "--prune", "--all"], cwd=path)
+        time.sleep(30 * 60) # 30 minutes
 
 # Check to see if this is running already. If so, kill it and rerun
 if os.path.exists(tmpfile) and os.path.isfile(tmpfile):
@@ -109,7 +105,7 @@ elif os.path.exists(tmpfile) and not os.path.isfile(tmpfile):
     raise Exception("/tmp/.buildworker-janitor is a directory. remove it to continue.")
 try:
     os.unlink(tmpfile)
-except:
+except Exception:
     pass
 with open(tmpfile, 'w') as f:
     print(os.getpid(), file=f)