diff --git a/dockertidy/Autostop.py b/dockertidy/Autostop.py
index d3ea278..36c6b2c 100644
--- a/dockertidy/Autostop.py
+++ b/dockertidy/Autostop.py
@@ -44,8 +44,11 @@ class AutoStop:
                 prefix and matcher(name) and self._has_been_running_since(container, max_run_time)
             ) or (not prefix and self._has_been_running_since(container, max_run_time)):
                 self.logger.info(
-                    "Stopping container %s %s: running since %s" %
-                    (container["Id"][:16], name, container["State"]["StartedAt"])
+                    "Stopping container {id} {name}: running since {started}".format(
+                        id=container["Id"][:16],
+                        name=name,
+                        started=container["State"]["StartedAt"]
+                    )
                 )
 
                 if not dry_run:
@@ -55,9 +58,9 @@ class AutoStop:
         try:
             client.stop(cid)
         except requests.exceptions.Timeout as e:
-            self.logger.warn("Failed to stop container %s: %s" % (cid, e))
-        except docker.errors.APIError as ae:
-            self.logger.warn("Error stopping %s: %s" % (cid, ae))
+            self.logger.warn("Failed to stop container {id}: {msg}".format(id=cid, msg=str(e)))
+        except docker.errors.APIError as e:
+            self.logger.warn("Error stopping {id}: {msg}".format(id=cid, msg=str(e)))
 
     def _build_container_matcher(self, prefixes):
 
diff --git a/dockertidy/Exception.py b/dockertidy/Exception.py
index 01f28b5..87c9f76 100644
--- a/dockertidy/Exception.py
+++ b/dockertidy/Exception.py
@@ -6,7 +6,7 @@ class TidyError(Exception):
     """Generic exception class for docker-tidy."""
 
     def __init__(self, msg, original_exception=""):
-        super(TidyError, self).__init__(msg + ("\n%s" % original_exception))
+        super(TidyError, self).__init__("{msg}\n{org}".format(msg=msg, org=original_exception))
         self.original_exception = original_exception
 
 
diff --git a/dockertidy/GarbageCollector.py b/dockertidy/GarbageCollector.py
index 6c82684..77cfd59 100644
--- a/dockertidy/GarbageCollector.py
+++ b/dockertidy/GarbageCollector.py
@@ -181,7 +181,7 @@ class GarbageCollector:
             image_tags = image_summary.get("RepoTags")
             if self._no_image_tags(image_tags):
                 # The repr of the image Id used by client.containers()
-                return set(["%s:latest" % image_summary["Id"][:12]])
+                return set(["{id}:latest".format(id=image_summary["Id"][:12])])
             return set(image_tags)
 
         def image_not_in_use(image_summary):
@@ -210,7 +210,9 @@ class GarbageCollector:
         if not image or not self._is_image_old(image, min_date):
             return
 
-        self.logger.info("Removing image %s" % self._format_image(image, image_summary))
+        self.logger.info(
+            "Removing image {name}".format(name=self._format_image(image, image_summary))
+        )
         if config["dry_run"]:
             return
 
@@ -230,7 +232,7 @@ class GarbageCollector:
         if not volume:
             return
 
-        self.logger.info("Removing volume %s" % volume["Name"])
+        self.logger.info("Removing volume {name}".format(name=volume["Name"]))
         if config["dry_run"]:
             return
 
@@ -249,11 +251,19 @@ class GarbageCollector:
         try:
             return func(**kwargs)
         except requests.exceptions.Timeout as e:
-            params = ",".join("%s=%s" % item for item in kwargs.items())
-            self.logger.warn("Failed to call %s %s %s" % (func.__name__, params, e))
-        except docker.errors.APIError as ae:
-            params = ",".join("%s=%s" % item for item in kwargs.items())
-            self.logger.warn("Error calling %s %s %s" % (func.__name__, params, ae))
+            params = ",".join("%s=%s" % item for item in kwargs.items())  # noqa
+            self.logger.warn(
+                "Failed to call {name} {params} {msg}".format(
+                    name=func.__name__, params=params, msg=str(e)
+                )
+            )
+        except docker.errors.APIError as e:
+            params = ",".join("%s=%s" % item for item in kwargs.items())  # noqa
+            self.logger.warn(
+                "Error calling {name} {params} {msg}".format(
+                    name=func.__name__, params=params, msg=str(e)
+                )
+            )
 
     def _format_image(self, image, image_summary):
 
@@ -263,7 +273,7 @@ class GarbageCollector:
                 return ""
             return ", ".join(tags)
 
-        return "%s %s" % (image["Id"][:16], get_tags())
+        return "{id} {tags}".format(id=image["Id"][:16], tags=get_tags())
 
     def _build_exclude_set(self):
         config = self.config.config
diff --git a/setup.py b/setup.py
index 689045d..47c4bae 100644
--- a/setup.py
+++ b/setup.py
@@ -81,7 +81,7 @@ setup(
         "jsonschema==3.2.0",
         "marshmallow==3.5.1",
         "nested-lookup==0.2.21",
-        "pathspec==0.7.0",
+        "pathspec==0.8.0",
         "pyrsistent==0.16.0",
         "python-dateutil==2.8.1",
         "python-dotenv==0.12.0",