When the categories that you've assigned to Account, Business Contact, Opportunity, or Business Project records are no longer useful for your tracking purposes, you can remove the categories.
Remove a category from the Color Categories list
On the Business Contact Manager menu, click Accounts, Business Contacts, Opportunities, or Business Projects.
To view records by category, on the View menu, point to Arrange By, point to Current View, and then click By Category.
On the Edit menu, point to Categorize, and then click All Categories.
In the Color Categories dialog box, click the category that you want to delete, and then click Delete.
When prompted, click Yes.
Note: When you delete a category, it is removed from the Color Categories list. If it is a standard category, Account, Business Contacts, Opportunity, and Business Project records retain their category assignments, so you can continue to find, sort, filter, or group your records by those deleted categories. However, if it is a custom category, and that category is deleted, the records lose their category assignment.