No problem JoAnn, we get a lot of questions about how to prevent tarnish on metals as well as preservatives for organic items. The best product for both jobs is the same, Krylon Crystal Clear Acrylic Spray Protectant, which is available at many craft and home improvement stores.
Here are several of the uses we've discussed regarding Krylon's Spray Protectant.
Anodized Aluminum and Chipping:
Protect colored metal with a coat of Krylon Crystal Clear Spray.
Seashell Jewelry with an Underwater Finish:
Keep sea shells bright and protected with this acrylic spray.
Rock Tumbling 101:
Give slabs a nice glossy finish while polishing your stones.
And on Krylon's own site, a helpful page about how to spray safely: Krylon's Spraying Safe Tips.
Answer contributed by Dale "Cougar" Armstrong