---
title: Non-serializable Properties | Tutorial
contributors:
  - jmmon
  - adamdbradley
  - manucorporat
  - tidiview
  - mrhoodz
updated_at: '2023-06-25T19:43:33Z'
created_at: '2022-08-02T12:07:45Z'
---

Stores must always be serializable, however sometimes you may want to persist a value on a store that can't be serialized. Values like these persist in the browser only when the application is resumed on the client.

When the application is paused, non-serializable properties are discarded.

> **Your task**: Add a cleanup function in `store.cleanup` so that the `stop` button can clear the interval with `clearInterval()`.
> For that, add `noSerialize` import from '@builder.io/qwik' and use `noSerialize` function to wrap clearInterval function.
