These Smelly Jelly Air Freshners can be used in any room of your house as well as in your vehicle. The jar has a removable disk under the lid. You just remove it and put the lid back on. Or you can punch out holes in the top for less of a scent throw. These can also be used in a simmer pot to create your favorite scent throughout your house. So many great ways to use these wonderful Smelly Jelly's! These make wonderful and inexpensive gifts as well! These come in assorted colors and many scents. These are light scent items. They do not give off a super strong smell so be aware that these are "light scent" item. Some scents are stronger than others, of course. If you want a really strong, fill the house with scent experience, try putting the smelly jelly in a potpourri crock. Absolutely wonderful this way!