# Non-serializable Properties > * 如有錯誤處指正或任何建議，懇請留言，感謝! > * 搭配 ChatGPT 進行翻譯，請小心服用 > * ▸ ... 為英文原文 :::spoiler ... 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. ::: ###### tags: `Stores`