diff --git a/lib/jekyll.rb b/lib/jekyll.rb
index 3f575837..5ff25deb 100644
--- a/lib/jekyll.rb
+++ b/lib/jekyll.rb
@@ -42,6 +42,7 @@ require 'jekyll/filters'
 require 'jekyll/static_file'
 require 'jekyll/errors'
 require 'jekyll/related_posts'
+require 'jekyll/cleaner'
 
 # extensions
 require 'jekyll/plugin'
diff --git a/lib/jekyll/cleaner.rb b/lib/jekyll/cleaner.rb
new file mode 100644
index 00000000..a933b9e2
--- /dev/null
+++ b/lib/jekyll/cleaner.rb
@@ -0,0 +1,73 @@
+require 'set'
+
+module Jekyll
+  class Site
+    # Handles the cleanup of a site's destination before the site is built.
+    class Cleaner
+      def initialize(site)
+        @site = site
+      end
+
+      # Cleans up the site's destination directory
+      def cleanup!
+        FileUtils.rm_rf(obsolete_files)
+      end
+
+      private
+
+      # Private: The list of files and directories to be deleted during the cleanup process
+      #
+      # Returns an Array with the file and directory paths
+      def obsolete_files
+        (existing_files - new_files - new_dirs + replaced_files).to_a
+      end
+
+      # Private: The list of existing files, except those included in keep_files and hidden files.
+      #
+      # Returns a Set with the file paths
+      def existing_files
+        files = Set.new
+        Dir.glob(File.join(@site.dest, "**", "*"), File::FNM_DOTMATCH) do |file|
+          files << file unless file =~ /\/\.{1,2}$/ || file =~ keep_file_regex
+        end
+        files
+      end
+
+      # Private: The list of files to be created when the site is built.
+      #
+      # Returns a Set with the file paths
+      def new_files
+        files = Set.new
+        @site.each_site_file { |item| files << item.destination(@site.dest) }
+        files
+      end
+
+      # Private: The list of directories to be created when the site is built.
+      # These are the parent directories of the files in #new_files.
+      #
+      # Returns a Set with the directory paths
+      def new_dirs
+        new_files.map { |file| File.dirname(file) }.to_set
+      end
+
+      # Private: The list of existing files that will be replaced by a directory during build
+      #
+      # Returns a Set with the file paths
+      def replaced_files
+        new_dirs.select { |dir| File.file?(dir) }.to_set
+      end
+
+      # Private: creates a regular expression from the config's keep_files array
+      #
+      # Examples
+      #   ['.git','.svn'] creates the following regex: /\/(\.git|\/.svn)/
+      #
+      # Returns the regular expression
+      def keep_file_regex
+        or_list = @site.keep_files.join("|")
+        pattern = "\/(#{or_list.gsub(".", "\.")})"
+        Regexp.new pattern
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/jekyll/site.rb b/lib/jekyll/site.rb
index f7a8c379..7f2cda2e 100644
--- a/lib/jekyll/site.rb
+++ b/lib/jekyll/site.rb
@@ -1,5 +1,3 @@
-require 'set'
-
 module Jekyll
   class Site
     attr_accessor :config, :layouts, :posts, :pages, :static_files,
@@ -228,43 +226,7 @@ module Jekyll
     #
     # Returns nothing.
     def cleanup
-      # all files and directories in destination, including hidden ones
-      dest_files = Set.new
-      Dir.glob(File.join(self.dest, "**", "*"), File::FNM_DOTMATCH) do |file|
-        if self.keep_files.length > 0
-          dest_files << file unless file =~ /\/\.{1,2}$/ || file =~ keep_file_regex
-        else
-          dest_files << file unless file =~ /\/\.{1,2}$/
-        end
-      end
-
-      # files to be written
-      files = Set.new
-      each_site_file { |item| files << item.destination(self.dest) }
-
-      # adding files' parent directories
-      dirs = Set.new
-      files.each { |file| dirs << File.dirname(file) }
-      files.merge(dirs)
-
-      # files that are replaced by dirs should be deleted
-      files_to_delete = Set.new
-      dirs.each { |dir| files_to_delete << dir if File.file?(dir) }
-
-      obsolete_files = dest_files - files + files_to_delete
-      FileUtils.rm_rf(obsolete_files.to_a)
-    end
-
-    # Private: creates a regular expression from the keep_files array
-    #
-    # Examples
-    #   ['.git','.svn'] creates the following regex: /\/(\.git|\/.svn)/
-    #
-    # Returns the regular expression
-    def keep_file_regex
-      or_list = self.keep_files.join("|")
-      pattern = "\/(#{or_list.gsub(".", "\.")})"
-      Regexp.new pattern
+      site_cleaner.cleanup!
     end
 
     # Write static files, pages, and posts.
@@ -422,5 +384,9 @@ module Jekyll
       limit = self.posts.length < limit_posts ? self.posts.length : limit_posts
       self.posts = self.posts[-limit, limit]
     end
+
+    def site_cleaner
+      @site_cleaner ||= Cleaner.new(self)
+    end
   end
 end