diff --git a/src/bot/bot.py b/src/bot/bot.py
index d7f74a1..31de065 100644
--- a/src/bot/bot.py
+++ b/src/bot/bot.py
@@ -503,8 +503,70 @@ async def cmd_help(update: Update, ctx: ContextTypes.DEFAULT_TYPE):
 
 # ─── Bot setup ────────────────────────────────────────────────────────────────
 
+async def _purge_on_startup(app: Application) -> None:
+    db_conn = await get_db()
+    try:
+        db = ResearchDB(db_conn)
+        result = await db.purge_old_sessions(30)
+        if result["sessions"] > 0:
+            logger.info("Startup purge done", **result)
+    except Exception as e:
+        logger.warning("Startup purge failed — bot continues", error=str(e))
+    finally:
+        await db_conn.close()
+
+
+async def cmd_purge(update: Update, ctx: ContextTypes.DEFAULT_TYPE):
+    if not is_authorized(update.effective_user.id):
+        return
+
+    args = ctx.args or []
+
+    if not args:
+        days = 30
+    else:
+        try:
+            days = int(args[0])
+        except ValueError:
+            await update.message.reply_text(
+                "❌ Uso: `/purge [días]`", parse_mode=ParseMode.MARKDOWN
+            )
+            return
+        if days < 0:
+            await update.message.reply_text("❌ El número de días debe ser ≥ 0.")
+            return
+        if days == 0 and not (len(args) >= 2 and args[1] == "confirm"):
+            await update.message.reply_text(
+                "⚠️ Esto borrará *todas* las sesiones completadas.\n"
+                "Envía `/purge 0 confirm` para confirmar.",
+                parse_mode=ParseMode.MARKDOWN
+            )
+            return
+
+    db_conn = await get_db()
+    try:
+        db = ResearchDB(db_conn)
+        result = await db.purge_old_sessions(days)
+        await update.message.reply_text(
+            f"🗑️ Purged: {result['sessions']} sessions, "
+            f"{result['sources']} sources, "
+            f"{result['chunks']} chunks, "
+            f"{result['outputs']} outputs"
+        )
+    except Exception as e:
+        logger.error("Purge command failed", error=str(e))
+        await update.message.reply_text(f"❌ Purge failed: {str(e)[:200]}")
+    finally:
+        await db_conn.close()
+
+
 def create_bot() -> Application:
-    app = Application.builder().token(settings.telegram_bot_token).build()
+    app = (
+        Application.builder()
+        .token(settings.telegram_bot_token)
+        .post_init(_purge_on_startup)
+        .build()
+    )
 
     app.add_handler(CommandHandler("start", cmd_start))
     app.add_handler(CommandHandler("help", cmd_help))
@@ -516,6 +578,7 @@ def create_bot() -> Application:
     app.add_handler(CommandHandler("outputs", cmd_outputs))
     app.add_handler(CommandHandler("process", cmd_process))
     app.add_handler(CommandHandler("cancel", cmd_cancel))
+    app.add_handler(CommandHandler("purge", cmd_purge))
 
     return app
 
diff --git a/src/db/database.py b/src/db/database.py
index eb0352c..c8561f8 100644
--- a/src/db/database.py
+++ b/src/db/database.py
@@ -5,8 +5,12 @@ from pathlib import Path
 from typing import Optional
 from enum import Enum
 
+import structlog
+
 from src.config import settings
 
+logger = structlog.get_logger()
+
 
 class ResearchStatus(str, Enum):
     RUNNING = "running"
@@ -266,3 +270,36 @@ class ResearchDB:
         )
         rows = await cursor.fetchall()
         return [dict(r) for r in rows]
+
+    # --- Maintenance ---
+
+    async def purge_old_sessions(self, max_age_days: int = 30) -> dict:
+        await self.db.execute("PRAGMA foreign_keys = ON")
+
+        threshold = time.time() - max_age_days * 86400
+        cursor = await self.db.execute(
+            "SELECT id FROM research_sessions WHERE created_at < ? AND status != 'running'",
+            (threshold,)
+        )
+        session_ids = [row[0] for row in await cursor.fetchall()]
+
+        counts = {"sessions": 0, "sources": 0, "chunks": 0, "outputs": 0}
+
+        for sid in session_ids:
+            await self.db.execute(
+                "DELETE FROM source_contents WHERE source_id IN (SELECT id FROM sources WHERE session_id = ?)",
+                (sid,)
+            )
+            cur = await self.db.execute("DELETE FROM chunks WHERE session_id = ?", (sid,))
+            counts["chunks"] += cur.rowcount
+            cur = await self.db.execute("DELETE FROM outputs WHERE session_id = ?", (sid,))
+            counts["outputs"] += cur.rowcount
+            cur = await self.db.execute("DELETE FROM sources WHERE session_id = ?", (sid,))
+            counts["sources"] += cur.rowcount
+            cur = await self.db.execute("DELETE FROM research_sessions WHERE id = ?", (sid,))
+            counts["sessions"] += cur.rowcount
+
+        await self.db.commit()
+        logger.info("Purged sessions older than days",
+                    sessions=counts["sessions"], days=max_age_days)
+        return counts