polish C# dependencies
diff --git a/templates/tools/dockerfile/csharp_deps.include b/templates/tools/dockerfile/csharp_deps.include
index 553eacb..489dc44 100644
--- a/templates/tools/dockerfile/csharp_deps.include
+++ b/templates/tools/dockerfile/csharp_deps.include
@@ -11,10 +11,6 @@
 # Install dependencies
 RUN apt-get update && apt-get -y dist-upgrade && apt-get install -y ${'\\'}
     mono-devel ${'\\'}
-    nunit ${'\\'}
-    nunit-console ${'\\'}
-    monodevelop
-
-# Download NuGet
-RUN cd /var/local && wget www.nuget.org/NuGet.exe
-ENV NUGET mono /var/local/NuGet.exe
+    ca-certificates-mono ${'\\'}
+    nuget ${'\\'}
+    && apt-get clean
diff --git a/tools/run_tests/pre_build_csharp.sh b/tools/run_tests/pre_build_csharp.sh
index 4341c02..32466c2 100755
--- a/tools/run_tests/pre_build_csharp.sh
+++ b/tools/run_tests/pre_build_csharp.sh
@@ -39,8 +39,3 @@
 then
   nuget restore Grpc.sln
 fi
-
-if [ -n "$NUGET" ]
-then
-  $NUGET restore Grpc.sln
-fi