Using these Libbey Gibraltar old - fashioned glasses is a breeze. Just pour your favorite old - fashioned cocktails, whiskey, bourbon, or scotch into the glass and enjoy. When it comes to cleaning, you can simply toss them in the dishwasher as they're dishwasher - safe. This saves you time and effort. For maintenance, since they have a DuraTuff® treatment, they're quite resistant to thermal and mechanical shock, but still, try to avoid dropping them on hard surfaces. Also, keep them in a dry place when not in use to prevent any possible damage. These glasses come in a case of 36, so you can easily stock up your bar or restaurant. With their classic design and durability, they're a great addition to any drinking setup.