diff --git a/backend/app.py b/backend/app.py
index 18df0ff..c92e436 100644
--- a/backend/app.py
+++ b/backend/app.py
@@ -162,7 +162,7 @@ def cleanup_job(job_id: str, req: CleanupRequest) -> CleanupResponse:
     except (IndexError, ValueError):
         vmid = 0
     logger.info("Cleanup: job=%s vmid=%d delete=%s", job_id, vmid, req.delete_staging_files)
-    result = cleanup_staging(vmid, req.delete_staging_files)
+    result = cleanup_staging(vmid, req.delete_staging_files, req.session_id)
     return CleanupResponse(
         job_id=result["job_id"],
         action_taken=result["action_taken"],
diff --git a/backend/models.py b/backend/models.py
index f1bb243..9aa697a 100644
--- a/backend/models.py
+++ b/backend/models.py
@@ -62,6 +62,7 @@ class JobSubmissionRequest(BaseModel):
 
 class CleanupRequest(BaseModel):
     delete_staging_files: bool
+    session_id: str = ""
 
 
 # ---------------------------------------------------------------------------
diff --git a/backend/provisioner.py b/backend/provisioner.py
index f601a6d..6504616 100644
--- a/backend/provisioner.py
+++ b/backend/provisioner.py
@@ -125,9 +125,8 @@ def clone_vm(req: CloneRequest) -> JobStatusResponse:
 
 
 def cleanup_staging(vmid: int, delete: bool, session_id: str = "") -> dict:
-    """Remove staging files for a VM ID."""
-    out_dir = _staging_out(session_id) / str(vmid)
-
+    """Remove staging files. If delete=True and session_id is set,
+    removes the entire session directory (both in/ and out/)."""
     if not delete:
         return {
             "job_id": f"job_{vmid}",
@@ -135,6 +134,20 @@ def cleanup_staging(vmid: int, delete: bool, session_id: str = "") -> dict:
             "message": f"Staging files preserved for VM {vmid}",
         }
 
+    # Delete the entire session tmp directory if we have a session ID
+    if session_id:
+        session_dir = STAGING_ROOT / session_id
+        if session_dir.exists():
+            shutil.rmtree(session_dir, ignore_errors=True)
+            logger.info("Cleaned up session dir: %s", session_dir)
+        return {
+            "job_id": f"job_{vmid}",
+            "action_taken": "purged",
+            "message": "Session files deleted.",
+        }
+
+    # Fallback: delete just the VM output dir
+    out_dir = _staging_out(session_id) / str(vmid)
     if out_dir.exists():
         shutil.rmtree(out_dir, ignore_errors=True)
         logger.info("Cleaned up output dir: %s", out_dir)
diff --git a/frontend/api_client.py b/frontend/api_client.py
index 91a1930..f743a4a 100644
--- a/frontend/api_client.py
+++ b/frontend/api_client.py
@@ -59,9 +59,12 @@ class ApiClient:
         """GET /api/v1/jobs/{job_id} — poll job status."""
         return self._get(f"/api/v1/jobs/{job_id}")
 
-    def cleanup_job(self, job_id: str, delete: bool) -> dict:
+    def cleanup_job(self, job_id: str, delete: bool, session_id: str = "") -> dict:
         """POST /api/v1/jobs/{job_id}/cleanup — remove or keep staging files."""
-        return self._post(f"/api/v1/jobs/{job_id}/cleanup", {"delete_staging_files": delete})
+        return self._post(f"/api/v1/jobs/{job_id}/cleanup", {
+            "delete_staging_files": delete,
+            "session_id": session_id,
+        })
 
     def clone_vm(self, source_vmid: int, target_vmid: int, target_name: str) -> dict:
         """POST /api/v1/clone — clone an existing VM."""
diff --git a/frontend/app.py b/frontend/app.py
index a23ae1b..4694680 100644
--- a/frontend/app.py
+++ b/frontend/app.py
@@ -519,7 +519,8 @@ async def session_cleanup(job_id: str, request: Request):
     try:
         body = await request.json()
         delete = body.get("delete_staging_files", False)
-        return api.cleanup_job(job_id, delete)
+        session_id = body.get("session_id", "")
+        return api.cleanup_job(job_id, delete, session_id)
     except ApiError as exc:
         return JSONResponse({"error": exc.detail}, status_code=502)
 
diff --git a/frontend/templates/index.html b/frontend/templates/index.html
index d971aa5..417d9eb 100644
--- a/frontend/templates/index.html
+++ b/frontend/templates/index.html
@@ -371,7 +371,7 @@ async function reuseImage(jobId, vmid, sourceFilename, keep) {
   try {
     await fetch('/session/cleanup/' + jobId, {
       method: 'POST', headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ delete_staging_files: true }),
+      body: JSON.stringify({ delete_staging_files: true, session_id: window.VM_BENCH_SID || '' }),
     });
     window.location.href = '/';
   } catch (err) { alert('Cleanup failed: ' + err.message); }