diff --git a/internal/rosa/all.go b/internal/rosa/all.go
index 4b87ed69..fefd3863 100644
--- a/internal/rosa/all.go
+++ b/internal/rosa/all.go
@@ -307,6 +307,17 @@ var (
 	artifactsOnce [_toolchainEnd][len(artifactsM)]sync.Once
 )
 
+// zero zeros the value pointed to by p.
+func zero[T any](p *T) { var v T; *p = v }
+
+// DropCaches arranges for all cached [pkg.Artifact] to be freed some time after
+// it returns. Must not be used concurrently with any other function from this
+// package.
+func DropCaches() {
+	zero(&artifacts)
+	zero(&artifactsOnce)
+}
+
 // GetMetadata returns [Metadata] of a [PArtifact].
 func GetMetadata(p PArtifact) *Metadata { return &artifactsM[p] }
 
diff --git a/internal/rosa/rosa_test.go b/internal/rosa/rosa_test.go
index 18d7b99b..ba51b248 100644
--- a/internal/rosa/rosa_test.go
+++ b/internal/rosa/rosa_test.go
@@ -91,3 +91,13 @@ func TestCureAll(t *testing.T) {
 		})
 	}
 }
+
+func BenchmarkStage3(b *testing.B) {
+	for b.Loop() {
+		rosa.Std.Load(rosa.LLVMClang)
+
+		b.StopTimer()
+		rosa.DropCaches()
+		b.StartTimer()
+	}
+}