Many times you might find your printer list is overloaded with printers you don't need/want for various reasons (new building assignment, printer was moved, broke down, etc). Luckily, removing printers is simple and only take a few seconds following the steps below.
1. Open System Preferences (click the Apple Logo in the upper-left, then System Preferences)
2. Click the "Printers & Scanners" icon in the middle-right part of the window
3. Click the printer (or select multiple by holding the command key while you click) you wish to delete, then click the "-" icon to delete.
4. When prompted, confirm that you want to delete the selected printer(s). The printer should be removed from your list after that.
The most current list of printers available at your school can be found in the Self Service app on your computer (click the magnifying glass in the upper-right corner and search for Self Service to find/launch that app).