diff --git a/bulk-compiler.sh b/bulk-compiler.sh
index 92d57eb..18756c3 100755
--- a/bulk-compiler.sh
+++ b/bulk-compiler.sh
@@ -13,6 +13,8 @@ find build/ -type f |
   while read BUILD BUILT GEM_NAME GEM_VERSION; do
     test -f "${BUILT}" && continue
 
+    unset EXTRA_PKGS EXTRA_GEMS GEM_COMPILER_FLAGS
+
     source "${BUILD}"
 
     HTTP_BASIC_USER="${HTTP_BASIC_USER}" \