How do I delete something from the database entirely?

The only way to delete something from the database entirely is to do a master data reset, and this is completed by going into the back office and going to Activities at the top of the screen then scrolling down to Maintenance Activities and clicking on Delete Master Data at the bottom of the list. 

Note: you can always delete something in the database if it has never been used and has no data associated with it.

Warning A Full reset of database erases all sales data and employee time cards..