diff --git a/src/pylorax/instroot.py b/src/pylorax/instroot.py
index b56b3323..c140a44f 100644
--- a/src/pylorax/instroot.py
+++ b/src/pylorax/instroot.py
@@ -95,7 +95,9 @@ def createInstRoot(yumconf=None, arch=None, treedir=None, updates=None):
         sys.stderr.write("ERROR: Could not install packages.\n")
         sys.exit(1)
 
-    # XXX: more coming!
+    if not scrubInstRoot(destdir=destdir):
+        sys.stderr.write("ERROR: Could not scrub instroot.\n")
+        sys.exit(1)
 
     return True
 
@@ -124,13 +126,129 @@ def installPackages(yumconf=None, destdir=None, packages=None):
     arglist += ['install', '-y'] + packages
 
     # do some prep work on the destdir before calling yum
-    os.makedirs(os.path.join(destdir, 'var', 'lib'))
     os.makedirs(os.path.join(destdir, 'tmp'))
     os.makedirs(os.path.join(destdir, 'var', 'log'))
-    os.makedirs(os.path.join(destdir, 'var', 'lib', 'yum'))
+    os.makedirs(os.path.join(destdir, 'var', 'lib'))
     os.symlink(os.path.join(os.path.sep, 'tmp'), os.path.join(destdir, 'var', 'lib', 'xkb'))
 
     # XXX: sort through yum errcodes and return False for actual bad things
     # we care about
     errcode = yummain.user_main(arglist, exit_code=False)
     return True
+
+# Scrub the instroot tree (remove files we don't want, modify settings, etc)
+def scrubInstRoot(destdir=None):
+    """scrubInstRoot(destdir=None)
+
+    Clean up the newly created instroot and make the tree more suitable to
+    run the installer.
+
+    destdir is the path to the instroot and is the only required argument.
+
+    """
+
+    if destdir is None or not os.path.isdir(destdir):
+        return False
+
+    # drop custom configuration files in to the instroot
+    dogtailconf = os.path.join(pylorax.conf['datadir'], 'dogtail-%conf.xml')
+    if os.path.isfile(dogtailconf):
+        os.makedirs(os.path.join(destdir, '.gconf', 'desktop', 'gnome', 'interface'))
+        f = open(os.path.join(destdir, '.gconf', 'desktop', '%gconf.xml'), 'w')
+        f.close()
+        f = open(os.path.join(destdir, '.gconf', 'desktop', 'gnome', '%gconf.xml'), 'w')
+        f.close()
+        dest = os.path.join(destdir, '.gconf', 'desktop', 'gnome', 'interface', '%gconf.xml')
+        shutil.copy(dogtailconf, dest)
+
+    # create selinux config
+    if os.path.isfile(os.path.join(destdir, 'etc', 'selinux', 'targeted')):
+        src = os.path.join(pylorax.conf['datadir'], 'selinux-config')
+        if os.path.isfile(src):
+            dest = os.path.join(destdir, 'etc', 'selinux', 'config')
+            shutil.copy(src, dest)
+
+    # create libuser.conf
+    src = os.path.join(pylorax.conf['datadir'], 'libuser.conf')
+    dest = os.path.join(destdir, 'etc', 'libuser.conf')
+    if os.path.isfile(src):
+        shutil.copy(src, dest)
+
+    # figure out the gtk+ theme to keep
+    gtkrc = os.path.join(destdir, 'etc', 'gtk-2.0', 'gtkrc')
+    gtk_theme_name = None
+    gtk_icon_themes = []
+    gtk_engine = None
+
+    if os.path.isfile(gtkrc):
+        f = open(gtkrc, 'r')
+        lines = f.readlines()
+        f.close()
+
+        for line in lines:
+            line = line.strip()
+            if line.startswith('gtk-theme-name'):
+                gtk_theme_name = line[line.find('=') + 1:].replace('"', '').strip()
+
+                # find the engine for this theme
+                gtkrc = os.path.join(destdir, 'usr', 'share', 'themes', gtk_theme_name, 'gtk-2.0', 'gtkrc')
+                if os.path.isfile(gtkrc):
+                    f = open(gtkrc, 'r')
+                    engine_lines = f.readlines()
+                    f.close()
+
+                    for engine_line in engine_lines:
+                        engine_line = engine_line.strip()
+
+                        if engine_line.find('engine') != -1:
+                            gtk_engine = engine_line[engine_line.find('"') + 1:].replace('"', '')
+                            break
+            if line.startswith('gtk-icon-theme-name'):
+                icon_theme = line[line.find('=') + 1:].replace('"', '').strip()
+                gtk_icon_themes.append(icon_theme)
+
+                # bring in all inherited themes
+                while icon_theme != '':
+                    icon_theme_index = os.path.join(destdir, 'usr', 'share', 'icons', icon_theme, 'index.theme')
+                    if os.path.isfile(icon_theme_index):
+                        f = open(icon_theme_index, 'r')
+                        icon_lines = f.readlines()
+                        f.close()
+
+                        for icon_line in icon_lines:
+                            icon_line = icon_line.strip()
+                            if icon_line.startswith('Inherits='):
+                                icon_theme = line[line.find('=') + 1:].replace('"', '')
+                                gtk_icon_themes.append(icon_theme)
+                                break
+                    else:
+                        icon_theme = ''
+
+    theme_path = os.path.join(destdir, 'usr', 'share', 'themes')
+    if os.path.isdir(theme_path):
+        for theme in os.listdir(theme_path):
+            if theme != gtk_theme_name:
+                theme = os.path.join(theme_path, theme)
+                shutil.rmtree(theme, ignore_error=True)
+
+    icon_path = os.path.join(destdir, 'usr', 'share', 'icons')
+    if os.path.isdir(icon_path):
+        for icon in os.listdir(icon_path):
+            try:
+                if gtk_icon_themes.index(icon):
+                    continue
+            except ValueError:
+                icon = os.path.join(icon_path, icon)
+                shutil.rmtree(icon, ignore_errors=True)
+
+    tmp_path = os.path.join(destdir, 'usr', libdir, 'gtk-2.0')
+    if os.path.isdir(tmp_path):
+        for subdir in os.listdir(tmp_path):
+            new_path = os.path.join(tmp_path, subdir, 'engines')
+            if os.path.isdir(new_path):
+                for engine in os.listdir(new_path):
+                    if engine.find(gtk_engine) == -1:
+                        tmp_engine = os.path.join(new_path, engine)
+                        os.unlink(tmp_engine)
+
+    return True