diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 679a997..2a6e8c2 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -57,4 +57,5 @@ jobs:
           nmake /NOLOGO /F Makefile.win
           nmake /NOLOGO /F Makefile.win install
           nmake /NOLOGO /F Makefile.win installcheck
+          nmake /NOLOGO /F Makefile.win clean
         shell: cmd
diff --git a/.gitignore b/.gitignore
index 592ee7f..e75301a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,7 @@ regression.*
 *.o
 *.so
 *.bc
+*.dll
+*.obj
+*.lib
+*.exp
diff --git a/Makefile.win b/Makefile.win
index 107f6c9..7bbdf9d 100644
--- a/Makefile.win
+++ b/Makefile.win
@@ -35,7 +35,7 @@ CFLAGS = /nologo /I"$(INCLUDEDIR_SERVER)\port\win32_msvc" /I"$(INCLUDEDIR_SERVER
 
 CFLAGS = $(CFLAGS) $(PG_CFLAGS)
 
-SHLIB = src\$(EXTENSION).dll
+SHLIB = $(EXTENSION).dll
 
 LIBS = "$(LIBDIR)\postgres.lib"
 
@@ -54,3 +54,9 @@ install:
 
 installcheck:
 	"$(BINDIR)\pg_regress" --bindir="$(BINDIR)" $(REGRESS_OPTS) $(REGRESS)
+
+clean:
+	rm -f $(SHLIB) $(EXTENSION).lib $(EXTENSION).exp
+	rm -f $(OBJS)
+	rm -rf sql\$(EXTENSION)--$(EXTVERSION).sql
+	rm -rf results regression.diffs regression.out tmp_check tmp_check_iso log output_iso