diff --git a/builds/libraries/libffi b/builds/libraries/libffi
index b29cf06..83b2255 100755
--- a/builds/libraries/libffi
+++ b/builds/libraries/libffi
@@ -14,10 +14,10 @@ cd autoconf-2.68
 make
 make install
 cd ..
-rm -fr autoconf-2.68
 
 # Use new Python path, containing autoconf.
 export PATH="/app/.heroku/python/bin/:$PATH"
+hash -r
 
 echo "Building libffi..."
 
@@ -34,4 +34,3 @@ make install
 
 # Cleanup
 cd ..
-rm -fr libffi