diff --git a/greg/aux_functions.py b/greg/aux_functions.py
index 48a7c24..870c423 100755
--- a/greg/aux_functions.py
+++ b/greg/aux_functions.py
@@ -137,8 +137,7 @@ def check_directory(placeholders):
     elif "yes" in subdirectory:
         subdnametemplate = feed.retrieve_config(
             "subdirectory_name", "{podcasttitle}")
-        subdname = substitute_placeholders(
-            subdnametemplate, placeholders)
+        subdname = placeholders.substitute(subdnametemplate)
         placeholders.directory = os.path.join(download_path, subdname)
     ensure_dir(placeholders.directory)
     placeholders.fullpath = os.path.join(
@@ -173,7 +172,7 @@ def tag(placeholders):
     """
     # We first recover the name of the file to be tagged...
     template = placeholders.feed.retrieve_config("file_to_tag", "{filename}")
-    filename = substitute_placeholders(template, placeholders)
+    filename = placeholders.substitute(template)
     podpath = os.path.join(placeholders.directory, filename)
     # ... and this is it
 
@@ -191,7 +190,7 @@ def tag(placeholders):
     except configparser.NoSectionError:
         pass
     for tag in tagdict:
-        metadata = substitute_placeholders(tagdict[tag], placeholders)
+        metadata = placeholders.substitute(tagdict[tag])
         tagdict[tag] = metadata
     file_to_tag = eyed3.load(podpath)
     if file_to_tag.tag == None:
@@ -211,7 +210,7 @@ def tag(placeholders):
 
 def filtercond(placeholders):
     template = placeholders.feed.retrieve_config("filter", "True")
-    condition = substitute_placeholders(template, placeholders)
+    condition = placeholders.substitute(template)
     return eval(condition)
 
 
@@ -240,7 +239,7 @@ def download_handler(feed, placeholders):
     value = feed.retrieve_config('downloadhandler', 'greg')
     if value == 'greg':
         filename_placeholders = feed.retrieve_config('downloaded_filename', '{filename}')
-        filename = substitute_placeholders(filename_placeholders, placeholders)
+        filename = placeholders.substitute(filename_placeholders)
         with urlopen(placeholders.link) as fin:
             # check if request went ok
             if fin.getcode() != 200:
@@ -257,7 +256,7 @@ def download_handler(feed, placeholders):
                 fout.write(fin.read())
     else:
         value_list = shlex.split(value)
-        instruction_list = [substitute_placeholders(part, placeholders) for
+        instruction_list = [placeholders.substitute(part) for
                             part in value_list]
         returncode = subprocess.call(instruction_list)
         if returncode:
diff --git a/greg/classes.py b/greg/classes.py
index 378040e..8381036 100644
--- a/greg/classes.py
+++ b/greg/classes.py
@@ -374,3 +374,22 @@ def __init__(self, feed, entry, link, filename, title, summary):
     def date_string(self):
         date_format = self.feed.retrieve_config("date_format", "%Y-%m-%d")
         return time.strftime(date_format, self.date)
+
+    def substitute(self, inputstring):
+        """
+        Take a string with placeholders, and return the strings with substitutions.
+        """
+        newst = inputstring.format(link=self.link,
+                                   filename=self.filename,
+                                   directory=self.directory,
+                                   fullpath=self.fullpath,
+                                   title=self.title,
+                                   filename_title=self.filename_title,
+                                   date=self.date_string(),
+                                   podcasttitle=self.podcasttitle,
+                                   filename_podcasttitle=
+                                   self.filename_podcasttitle,
+                                   name=self.name,
+                                   subtitle=self.sanitizedsubtitle,
+                                   entrysummary=self.entrysummary)
+        return newst