To remove a resource for a skill, click on Skills in the left navigation menu. On the Skills page, locate the skill for which you wish to remove a resource and click on the name of the skill.
By default, the Team Members tab is selected. Click on the Resources tab and locate the resource you wish to remove. Click the orange wrench icon in the Edit column. (Be careful to click on the orange wrench icon associated with the resource and not the same icon for the skill itself.) Next, click on the red wastebasket icon.
There will be no confirmation to delete the resource but you will have a moment to undo the deletion.