Please follow these simple steps in order to delete any unwanted Sales Price Lists.
Navigate to Sales
Click on Sales Price Lists
Press F5 into Price List Preference
Here you will have a list of all your Sales Price Lists
Press CTRL + M to enter Modify mode
Highlight the required Sales Price List and press F3 to delete
If one of the lists needed to delete is set as default you won't be able to delete it, to change this simply navigate to another list and press Set as Default in the bottom right corner
