diff --git a/3.10.0/onbuild/Dockerfile b/3.10.0/onbuild/Dockerfile
index b64ed01..924571a 100644
--- a/3.10.0/onbuild/Dockerfile
+++ b/3.10.0/onbuild/Dockerfile
@@ -2,11 +2,10 @@ FROM mono:3.10.0
 
 MAINTAINER Jo Shields <jo.shields@xamarin.com>
 
-RUN mkdir -p /usr/src/app/{source,build}
+RUN mkdir -p /usr/src/app/source /usr/src/app/build
 WORKDIR /usr/src/app/source
 
-ONBUILD ADD . /usr/src/app/source
+ONBUILD COPY . /usr/src/app/source
 ONBUILD RUN nuget restore -NonInteractive
 ONBUILD RUN xbuild /property:Configuration=Release /property:OutDir=/usr/src/app/build/
-ONBUILD RUN rm -rf /usr/src/app/source
 ONBUILD WORKDIR /usr/src/app/build
diff --git a/3.12.0/onbuild/Dockerfile b/3.12.0/onbuild/Dockerfile
index 94da5e4..8993d28 100644
--- a/3.12.0/onbuild/Dockerfile
+++ b/3.12.0/onbuild/Dockerfile
@@ -2,11 +2,10 @@ FROM mono:3.12.0
 
 MAINTAINER Jo Shields <jo.shields@xamarin.com>
 
-RUN mkdir -p /usr/src/app/{source,build}
+RUN mkdir -p /usr/src/app/source /usr/src/app/build
 WORKDIR /usr/src/app/source
 
-ONBUILD ADD . /usr/src/app/source
+ONBUILD COPY . /usr/src/app/source
 ONBUILD RUN nuget restore -NonInteractive
 ONBUILD RUN xbuild /property:Configuration=Release /property:OutDir=/usr/src/app/build/
-ONBUILD RUN rm -rf /usr/src/app/source
 ONBUILD WORKDIR /usr/src/app/build
diff --git a/3.8.0/onbuild/Dockerfile b/3.8.0/onbuild/Dockerfile
index ff899ec..93ef0b0 100644
--- a/3.8.0/onbuild/Dockerfile
+++ b/3.8.0/onbuild/Dockerfile
@@ -2,11 +2,10 @@ FROM mono:3.8.0
 
 MAINTAINER Jo Shields <jo.shields@xamarin.com>
 
-RUN mkdir -p /usr/src/app/{source,build}
+RUN mkdir -p /usr/src/app/source /usr/src/app/build
 WORKDIR /usr/src/app/source
 
-ONBUILD ADD . /usr/src/app/source
+ONBUILD COPY . /usr/src/app/source
 ONBUILD RUN nuget restore -NonInteractive
 ONBUILD RUN xbuild /property:Configuration=Release /property:OutDir=/usr/src/app/build/
-ONBUILD RUN rm -rf /usr/src/app/source
 ONBUILD WORKDIR /usr/src/app/build