diff --git a/repo2docker/buildpacks/base.py b/repo2docker/buildpacks/base.py
index 0235d1b2..3b8512be 100644
--- a/repo2docker/buildpacks/base.py
+++ b/repo2docker/buildpacks/base.py
@@ -1,6 +1,5 @@
 import textwrap
 from traitlets.config import LoggingConfigurable
-from traitlets import Unicode, Set, List, Dict, Tuple, default
 import jinja2
 import tarfile
 import io
diff --git a/repo2docker/buildpacks/conda/__init__.py b/repo2docker/buildpacks/conda/__init__.py
index 735ae428..099e19a4 100644
--- a/repo2docker/buildpacks/conda/__init__.py
+++ b/repo2docker/buildpacks/conda/__init__.py
@@ -6,7 +6,6 @@ import os
 import re
 
 from ruamel.yaml import YAML
-from traitlets import default, Unicode
 
 from ..base import BaseImage
 
diff --git a/repo2docker/buildpacks/julia.py b/repo2docker/buildpacks/julia.py
index 6fffa546..deae38a0 100644
--- a/repo2docker/buildpacks/julia.py
+++ b/repo2docker/buildpacks/julia.py
@@ -1,7 +1,6 @@
 """
 Generates a variety of Dockerfiles based on an input matrix
 """
-from traitlets import default
 import os
 from .conda import CondaBuildPack
 
diff --git a/repo2docker/buildpacks/python/__init__.py b/repo2docker/buildpacks/python/__init__.py
index 47007151..ab736180 100644
--- a/repo2docker/buildpacks/python/__init__.py
+++ b/repo2docker/buildpacks/python/__init__.py
@@ -1,7 +1,6 @@
 """
 Generates a variety of Dockerfiles based on an input matrix
 """
-from traitlets import default
 import os
 from ..base import BaseImage