# Clearing unused chart variables

**URL:** <https://discourse.nodered.org/t/clearing-unused-chart-variables/87210>\
**Category:** General\
**Created:** [12 April 2024 22:29 UTC](https://discourse.nodered.org/t/clearing-unused-chart-variables/87210 "2024-04-12T22:29:25Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rmystique](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rmystique/32/84365_2.png) [@rmystique](https://discourse.nodered.org/u/rmystique)\
**Post date:** [12 April 2024 22:29 UTC](https://discourse.nodered.org/t/clearing-unused-chart-variables/87210/1 "2024-04-12T22:29:26Z")

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I have a chart that I was trying different variables (topics) on it and I am saving the chart data for 4 days, and I have made name changes (topics) how do I clear out the old ones that I no longer use that show up in the legend?

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**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [12 April 2024 22:52 UTC](https://discourse.nodered.org/t/clearing-unused-chart-variables/87210/2 "2024-04-12T22:52:05Z")

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I think you send it an empty message like this:

(given it is using `msg.payload`)

`msg.payload = []`

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [26 April 2024 22:52 UTC](https://discourse.nodered.org/t/clearing-unused-chart-variables/87210/3 "2024-04-26T22:52:17Z")

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