My heroine, a wandering loner living a nomadic lifestyle traveling across 1998's western US in an RV, is a supernatural being, known as an immortal, with a great many useful powers. However, none of these powers are particularly effective for combat. While she can easily use her abilities to retreat from any situation with her life intact, she'd have to abandon her RV and all of her belongings to the mercy of her attackers if this were to happen while she was "home", so she needs some other options to defend herself. The most extreme of these is a S&W Model 29 revolver, fully loaded with six silver .44 rounds.
Silver is quite effective against nearly all types of immortals, her type included. However, even among people who know immortals are real and regularly deal with them, silver bullets are generally only used as a last resort, or by people who are extremely well-organized, for one very big reason: superhuman sense of smell is an incredibly common supernatural ability, and to any such supernaturally-augmented nose, silver, and especially the combined scent of silver and gunpowder, is one of the strongest and most distinctive smells on the planet. If such a bullet is even exposed to open air, any "bloodhounds" a mile around will be able to follow the smell right to you. If you actually fire one, that becomes somewhere between five to ten.
Therefore, among anyone who actually owns silver bullets, they are generally kept in completely air-tight containers until they're ready to be used, because nothing less than an air-tight seal will stop the smell from reaching a superhuman nose.
My heroine can use her powers to commit plenty of minor acts of home invasion and shoplifting with ease, but beyond that her resources aren't exactly high-budget. She needs a relatively-accessible means to store her revolver, pre-loaded so that she doesn't have to worry about loading it in a crisis, behind an air-tight seal that she doesn't have to worry too much about breaking accidentally, but which can also be removed reasonably quickly when the moment comes where she has to defend herself. What would be her best option given the location of the USA and the time period of 1998?