diff --git a/Dockerfile b/Dockerfile
index 9addfc3d4921f524d57a32dcce4335207e006daf..c4e3f95ad2d532bc4a67ecf96cf995ec93286468 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-# Docker image for building and testing adaptive
+# Docker image for testing adaptive
 FROM conda/miniconda3:latest
 
 # make our environment sane
@@ -8,4 +8,5 @@ ENV LC_ALL C.UTF-8
 COPY environment.yml test-requirements.txt /
 
 RUN conda env update --quiet -n root -f environment.yml
+RUN conda clean --yes --all
 RUN pip install -r test-requirements.txt