CLAYS
The nature of polymer clay after it has cured should be bendable, though to increase the longevity of your pieces doing so is not recommended. Store your pieces with care and use caution when packing/traveling.
ACRYLICS
Plated Charms: Gently rub charms with a soft cloth in warm soapy (dish soap) water. This should restore the charm's shine. Store your jewelry away from the open air/elements.
Acrylics: Resin becomes hard once it has cured. It is susceptible to scratching and chipping if not well cared for. Take caution when packing/traveling and store with care.
DECOR
Wreaths: I personally store my wreaths on top of my bins in a closet to avoid the flowers and other decorations from smushing. You can store your wreaths in a wreath container or on top of something that will not be stacked on.
Glass Ornaments: Glass itself is fragile, though glass ornaments are especially fragile. Store your ornaments wrapped in paper and in a box, protected from heavy items.