diff --git a/workers/durableObject/index.ts b/workers/durableObject/index.ts
index e2cbbfa3..37d3e92e 100644
--- a/workers/durableObject/index.ts
+++ b/workers/durableObject/index.ts
@@ -869,4 +869,46 @@ export class MailboxDO extends DurableObject<Env> {
 			this.db.insert(schema.attachments).values(attachments).run();
 		}
 	}
+
+	// ── Teardown ───────────────────────────────────────────────────────
+
+	/**
+	 * Tear down this mailbox: enumerate attachments, delete their R2 blobs,
+	 * wipe SQLite storage, and abort the DO so the next access gets a fresh
+	 * instance (which re-runs migrations on an empty DB).
+	 *
+	 * Attachment blob deletion happens here so the whole operation is atomic
+	 * from the caller's perspective and avoids shipping a potentially large
+	 * string[] back over RPC.
+	 */
+	async destroyMailbox(): Promise<void> {
+		const rows = [
+			...this.ctx.storage.sql.exec<{
+				email_id: string;
+				id: string;
+				filename: string;
+			}>(`SELECT email_id, id, filename FROM attachments`),
+		];
+		const keys = rows.map(
+			(r) => `attachments/${r.email_id}/${r.id}/${r.filename}`,
+		);
+
+		// R2 batch delete cap is 1000 keys per call.
+		for (let i = 0; i < keys.length; i += 1000) {
+			const chunk = keys.slice(i, i + 1000);
+			if (chunk.length > 0) await this.env.BUCKET.delete(chunk);
+		}
+
+		await this.ctx.storage.deleteAll();
+
+		// Abort so the next request against this mailbox-id gets a fresh DO
+		// instance and its constructor re-runs migrations on a new SQLite DB.
+		// Without this the live instance retains an empty DB without the
+		// d1_migrations tracker and schema-dependent methods would fail.
+		// `ctx.abort()` throws an uncatchable error, so defer to the event
+		// loop to let the RPC response flush first.
+		setTimeout(() => {
+			this.ctx.abort("destroyed");
+		}, 0);
+	}
 }
diff --git a/workers/index.ts b/workers/index.ts
index fd3359ce..2edeb322 100644
--- a/workers/index.ts
+++ b/workers/index.ts
@@ -136,7 +136,26 @@ app.delete("/api/v1/mailboxes/:mailboxId", async (c) => {
 	const mailboxId = c.req.param("mailboxId")!;
 	const key = `mailboxes/${mailboxId}.json`;
 	if (!(await c.env.BUCKET.head(key))) return c.json({ error: "Not found" }, 404);
-	await c.env.BUCKET.delete(key); // TODO: also delete DO data and R2 attachment blobs
+
+	// Drain the mailbox DO: delete R2 attachment blobs, wipe SQLite storage,
+	// and abort so the next access gets a fresh instance.
+	const mailboxStub = c.env.MAILBOX.get(c.env.MAILBOX.idFromName(mailboxId));
+	await (mailboxStub as any).destroyMailbox();
+
+	// Drain the EmailAgent DO via the inherited AIChatAgent.destroy() RPC.
+	// Upstream `Agent.destroy()` drops cf_agents_* tables, deletes the chat
+	// history (`cf_ai_chat_agent_messages`), deletes alarms, runs dispose
+	// hooks, wipes storage, and aborts the DO.
+	const agentStub = c.env.EMAIL_AGENT.get(c.env.EMAIL_AGENT.idFromName(mailboxId));
+	await (agentStub as any).destroy()
+		.catch((e: Error) => console.error("EmailAgent destroy failed:", e.message));
+
+	// Delete settings JSON last. A partial failure leaves the HEAD check
+	// passing so the operation can be retried. This is best-effort cleanup
+	// — a concurrent receiveEmail() that passed its HEAD check before this
+	// delete can still repopulate the mailbox; closing that race needs a
+	// deleting-flag coordination protocol and is out of scope here.
+	await c.env.BUCKET.delete(key);
 	return c.body(null, 204);
 });