Remove some data from a custom chart

I would like to remove the values of one of our builds from a custom chart I've created because its values are much higher than the rest and it makes the y-axis so large that I cannot properly inspect the graph for the other builds anymore.

How can I do that?

I've already tried to delete the folder with the artifacts for that specific build from the TC server disk but the graph keeps showing the values. Is there a cache I can delete to trigger a refresh of the charts data?