diff --git a/CalenTask/App/AppShellView.swift b/CalenTask/App/AppShellView.swift
index 29ba310..16bfbbc 100644
--- a/CalenTask/App/AppShellView.swift
+++ b/CalenTask/App/AppShellView.swift
@@ -118,6 +118,7 @@ struct AppShellView: View {
                 reportFailure("Seed failed: \(error)")
             }
             SmokeSeeder.seedIfRequested(in: modelContext)
+            TrashService.purgeExpired(in: modelContext)
             WidgetBridge.refresh(in: modelContext)
             WeatherService.shared.refreshIfNeeded()
             if !didShowWelcome {
diff --git a/CalenTask/Services/TrashService.swift b/CalenTask/Services/TrashService.swift
new file mode 100644
index 0000000..a6bdda1
--- /dev/null
+++ b/CalenTask/Services/TrashService.swift
@@ -0,0 +1,30 @@
+import Foundation
+import SwiftData
+
+/// #22 — Cestino: elimina in modo definitivo le attività cancellate (soft
+/// delete) da più di `retentionDays`, così DB e CloudKit non crescono per sempre.
+enum TrashService {
+    static let retentionDays = 30
+
+    /// Hard delete delle task con `deletedAt` oltre la soglia. Salta quelle che
+    /// hanno ancora sotto-attività vive (non si orfanano figli). Ritorna quante
+    /// ne ha eliminate.
+    @MainActor
+    @discardableResult
+    static func purgeExpired(in context: ModelContext, now: Date = .now) -> Int {
+        guard let cutoff = Calendar.app.date(byAdding: .day, value: -retentionDays, to: now) else { return 0 }
+        let predicate = #Predicate<TodoTask> { task in
+            task.deletedAt != nil
+        }
+        // Il cestino è piccolo: il filtro sulla soglia avviene in memoria.
+        let expired = context.fetchOrLog(FetchDescriptor<TodoTask>(predicate: predicate))
+        let purgeable = expired.filter { task in
+            guard let deletedAt = task.deletedAt else { return false }
+            return deletedAt < cutoff && task.liveSubtasks.isEmpty
+        }
+        guard !purgeable.isEmpty else { return 0 }
+        purgeable.forEach { context.delete($0) }
+        context.saveOrLog()
+        return purgeable.count
+    }
+}
diff --git a/CalenTaskTests/TrashServiceTests.swift b/CalenTaskTests/TrashServiceTests.swift
new file mode 100644
index 0000000..3f3a536
--- /dev/null
+++ b/CalenTaskTests/TrashServiceTests.swift
@@ -0,0 +1,38 @@
+import Foundation
+import SwiftData
+import Testing
+@testable import CalenTask
+
+/// #22 — `TrashService.purgeExpired`: elimina solo ciò che è nel cestino da oltre 30 giorni.
+@MainActor
+struct TrashServiceTests {
+
+    private func makeContext() throws -> ModelContext {
+        let schema = Schema([
+            Workspace.self, Membership.self, UserProfile.self,
+            Project.self, TodoTask.self, TaskDependency.self, Tag.self,
+            CustomFieldDefinition.self, CustomFieldValue.self, SavedView.self,
+            WorkflowStage.self, AutomationRule.self, Attachment.self,
+            Contact.self, CrewAssignment.self, ProductionScene.self,
+        ])
+        let config = ModelConfiguration(schema: schema, isStoredInMemoryOnly: true)
+        return ModelContext(try ModelContainer(for: schema, configurations: [config]))
+    }
+
+    @Test func purgesOnlyExpiredDeletedTasks() throws {
+        let context = try makeContext()
+        let now = Date(timeIntervalSince1970: 10_000_000)
+        let author = UUID(), ws = UUID()
+        let old = TodoTask(workspaceID: ws, title: "Vecchia", createdByID: author)
+        old.deletedAt = now.addingTimeInterval(-31 * 86_400)
+        let recent = TodoTask(workspaceID: ws, title: "Recente", createdByID: author)
+        recent.deletedAt = now.addingTimeInterval(-5 * 86_400)
+        let live = TodoTask(workspaceID: ws, title: "Viva", createdByID: author)
+        [old, recent, live].forEach { context.insert($0) }
+        try context.save()
+
+        #expect(TrashService.purgeExpired(in: context, now: now) == 1)
+        let titles = try context.fetch(FetchDescriptor<TodoTask>()).map(\.title).sorted()
+        #expect(titles == ["Recente", "Viva"])
+    }
+}