FOR KEEPS Preserving a gown

Beware of set gown-cleaning prices. Every gown is unique; every gown takes a different amount of time to process and clean, Penninger said.
Make sure you ask the cleaner for a sugar-stain treatment using an ultraviolet light to detect every spot, as invisible champagne or sugar stains (white wine, cake icing) will caramelize and look yellow-brown when you take the dress out of the box in 10 or 20 years.
Inspect the dress after cleaning. Then, make sure the cleaner wraps it in acid-free, archival-quality paper and stores it in an acid-free box. Put the box somewhere dry -- "never in an attic, never in a basement, never in an exterior-walled closet or garage," Penninger said.
Don't hang up the gown -- that will stretch it out of shape. Keep it flat.
Wedding gowns must be protected from light and air but not sealed in an airtight package. It's OK to take your dress out every now and again -- especially if a daughter wants to try it on. Tripp recommends taking the dress out annually (while wearing cotton gloves), refluffing the tissue and refolding the dress along new lines to avoid permanent creases.